Below there are a lot of questions about very specific situations and which won't matter that much. So if you don't like nitpicking questions, consider to stop reading. Also, I'm not really waiting for answers like "play as you want", but would rather like to know the "official" ruling. Or, if there's no official ruling, hear opinions why one alternative is more logical than the other.
Thanks in advance for answering these questions!
1 What happens if a monster is placed in the outskirts when the terror level is 10? (for example by Mother Hydra). If this happens as normal, what happens if the outskirts limit is reached? The terror level increases as normal? (meaning that a doom token is added to the doom track?). Related: if the terror level is 10, do you immediately add 1 doom token to the doom track or only for every additional terror level increase?
2 What do fliers do if they do not move to the Sky (for example with environment Angry Red Skies) and they move (with no investigator nearby)? Do they move as though they were a normal monster or do they stay where they are? (if they move as a normal monster: what happens with a gate burst: "all flying monsters move"? White or black?)
3 Exactly when can you default a bank loan? Is there indeed no penalty of defaulting if you currently have no items (except that you can't gain another one)?
4 When returning from LiTaS just before upkeep, do you pick up the clue tokens of you destination? In general, if you move somewhere in some other phase than the movement phase (for example in an encounter like: "move to … and immediately have an encounter there"), do you pick up the clues there?
5 Can you use items/spells in the movement phase if you are delayed (as long as they don't use movement points)? Or is the only action allowed standing up your investigator? In the last case, what happens if monsters are in the same location as you. You have to fight them, right?
6 Related to 5: When you're arrested and move you're investigator to the police station in the next movement phase, do you have to fight monsters that are in the police station (for example Hound of Tindalos)?
6.5 If you've had an encounter which says "lose your next turn" (as opposed to "be delayed" or "stay here next turn") you won't get any encounters and cannot use any cards next turn, right? Do you have to fight monsters in your location as normal, tough? Without weapons?
7 The .18 Derringer states ".18 Derringer cannot be lost or stolen unless you choose to allow it". How does this exactly work? If you have to discard a (common) item, can you choose the derringer, and after that say "but that item cannot be stolen, so I'll keep it", effectivelty negating the effect? Same question if you lose half of your items (for example when knocked unconscious). If both answers are "no", is the text of the Derringer then only useful if you lose all your items?
8 When you can use an item or spell in the upkeep, need this to be done in the "Perform Upkeep Actions"-subphase, or can you also do this in the "Adjust Skills"-subphase after using focus? If you can do it in the "Adjust Skills" phase, can you then move skill slider, cast spell, move skill slider back (provided that you have enough focus)?
9 Can you use "Powder of Ibn-Ghazi" (lose 1 sanity and discard to gain +9 to combat checks) when you have only 1 sanity to defeat a monster (and then go insane)? Or, if you're stupid enough to use it, will you merely go insane?
10 Sometimes the price of an item is relevant (there's an encounter which says you have to discard your most expensive item or something like that). What's the price of spells? What's the price of deputy's revolver and Patrol Wagon?
9.5 Are "The White Ship" and "The Great Seal" items? Are there other special cards considered items (except of Deputy's revolver and patrol wagon)?
11 If you use an item or spell to automatically pass some check, or add successes to that check, but the card does not state if it has to be used before rolling for the check or after rolling, when can you use it? Examples: Blue Watcher of the Pyramid, Mists of Releh,Bind Monster
12 Suppose you have an explored marker on a (moving) gate which is NOT in an unstable location. Can you use an elder sign (maybe only to close the gate)? If so, what happens?
13 About Flute of the Outer Gods ("Lose 3 Sanity and 3 Stamina and discard Flute of the Outer Gods before making a Combat check to defeat all monsters in your current area. This does not affect Ancient Ones."): Can it be used in a combat check from an encounter? If so, what happens to that combat check? If used against monsters, do you get damage from overwhelming of the monsters defeated this way? If there's a warlock (or something) in your location, do you get the clue tokens just as if you have passed a combat check against it?
14 Do "Blue Watcher of the Pyramid" and "Flute of the Outer Gods" work against the Dunwich Horror (which will make him a whole lot less unbeatable)?
15 Can Ruby of R'lyeh be used by more than 1 investigator in a single movement phase? If no, shouldn't the text be replace with "Exhaust to gain 3 movement points"? If yes, can an investigator during its movement grab the Ruby from another investigator, use it, and give it back immediately afterwards to gain 3 movement points?
16 Can Warding Statue ("Discard Warding Statue after failing a Combat check to reduce the monster's combat damage to 0 Stamina. This can also be used to cancel an Ancient One's entire attack for 1 turn.") also be used when failing an evade check against a monster? Does it also remove other effects when failing a combat check? (like losing an item against an Elder Thing)
17 Please give an algorithm to determine how much monster go where when a monster surge occurs. Please include the following problems:
-monsters being sent to the outskirts by the monster limit
-monster limit removed since this monster surge raised the terror level to 10
-expansions where monsters do not count against the monster limit
-the card "Warding of the Yellow Sign" being placed on the board ("When you gain this card, choose a location in Arkham and place this card there. No monsters may appear via gates in this location. Monsters that appear during encounters in this location may automatically be Evaded.")
If a general algorithm is too hard to give, please state what happens in the following scenarios:
(a)In the following example: 7 player game, 3 gates open: Devil Reef (Innsmouth), Independence Square and Graveyard. There are 9 monsters in Arkham, and the terror level is 0. A monster surge occurs in the Graveyard. Am I correct that there will be placed 2 monsters on Devil Reef, 1 in Graveyard, 0 in Independence Square and 4 in Outskirts (and then resolving that the outskirts is too full, raising the terror level by 2)?
(b)Same situation, except that the terror level now is 8 and there's 1 monster already in the Outskirts. Then after placing 3 monsters in the Outskirts, the terror level reaches 10 and Arkham is overrun. So then the logical place for the last monster would be Independence Square, right? But then we are in the confusing situation that there have been placed 2 monsters on Devil Reef, 1 in Graveyard, 1 on Independence Square and 3 in Outskirts, while the monster surge occurred in Graveyard, and no game mechanic prohibits the fact that 1 extra monster would have been placed in Graveyard (instead of Devil Reef).
©What does the card "Warding of the Yellow Sign" exactly do? Does this card work when monsters appear via a monster surge? If so, does this reduce the amount of monsters which appear as a result of this monster surge? Or will there appear more monsters from different gates? What happens if some or all monsters are placed in the outskirts? Will they be treated as "visited the location for a fraction of a second and then moved to the outskirts" (such that the card still has effect)?
18 In the encounter "You touch Founder's Rock. Make a Luck (-1) check. If you pass, there is an electrifying shock that opens your mind to the elder things of eons past. Lose 1 Stamina, but gain 2 Clue tokens and draw 1 Spell. If you fail, you find a strange carving. As you finger the grooves, a gate opens here and you are drawn through it." how many monsters appear out of this gate? The same number as if it stated "A gate and a monster appear" (so 1 or 2)?
19 What is the Hound of Tindalos distance function (include travel across different boards, devil's reef, y'ha-ntlei and kingsport head locations)?
20 Do spells still have effect when you go insane by paying its sanity cost?
21 Can you spend more sanity/stamina than you currently have? For example use bind monster on a very dangerous monster when you have only 1 sanity?
22 If you're arrested (or instructed by some encounter), you skip your next turn. What if the ancient one awakens later the same turn as you're arrested in, do you fight it normally the first turn?
23 When you're devoured (not in the final battle) exactly when does your new investigator enter play? Begin of the next upkeep phase? In the last case, can he get an arkham encounter before having a movement phase?
24 There are quite some encounters which state that you move to some other world, have an encounter there and immediately return. What happens if the encounter in the other world makes you Lost in Time and Space (you do not return then?), return to Arkham (do you just return to your original location, or to an open gate with an explored marker? Or are you lost in time and space if there's no open gate?), or delay you (you're just delayed after returning to arkham?)?
25 In the encounter "You are mistaken for an inmate. Doctor Mintz has the guards subdue you and conducts an experiment. Make a Will (-1)  check to discover the results. If you pass, the injections seem to increase your capacity for learning. Draw 1 Skill. If you fail, his memory drug fails miserably, resulting in lost knowledge. You must discard one of the following (your choice), if able: 4 Clue tokens, or 2 Spells, or 1 Skill.", if you fail, can you choose an option which you cannot discard (while you can discard one of the other options)? What if you can only partially discard something (for example you have 1 clue token, but two spells, are you allowed to discard the clue token)? If you cannot fully discard any of the options, should you choose an option where you can discard "most"? Does the same logic apply to the encounter "Sheriff Engle notes that you're carrying an awful lot of weapons. Either pay him $5 or discard all of your Weapons."? Because there it would seem rather silly that you have to pay 5 dollar if you do not carry any weapons.
26 If you get an Arkham Encounter "A gate and a monster appears", is it true that you will have 3 other world encounters before you can return to Arkham? (given that you won't be delayed, sent to LiTaS, return to Arkham early, etc.)
27 Some mythos cards (Strange Sightings!) have no gate opening, but say (in the headline) that a monster surge occurs. When does this happen, in the "open gate" part of the mythos phase or the "Activate Mythos Ability" part? Also, the first player gains a clue token, when is that done, "place clue token" part or "Activate Mythos Abililty" part (this does matter in rare cases)
28 Questions about The Black Man ("Before making a Horror check, pass a Luck (-1) check or be devoured. If you pass, gain 2 Clue tokens. In either case, return the Black Man to the cup."). Can you claim it as monster trophy with John Legrasse? Does passing the Luck -1 check count as "killing" the monster? (for encounters like "Two monsters surface from the island's dark waters. If you kill them both, you are Blessed.")
29 An encounter in the Curiositie Shoppe states "Draw a mythos card and move to the gate location shown on it". What happens if you draw a mythos card with 0 or 2 gates on it? Draw again?
30 If you go insane or unconscious during an encounter, but you have not done everything yet, do you complete the encounter? If so, when do you go insane/unconscious? Immediately upon reading "Lose X sanity/stamina", or after the encounter? Or does it depend on what happens next? What if you get "lose 1 sanity but gain 1 clue token"? Do you get the clue token (and before or after losing half of your clues)? And in "Lose 1 sanity and a monster appears", it is pretty clear that you won't have to find the monster if you go insane from the "lose 1 sanity". But what is less clear (and sometimes matters (Rhan-Tegoth)) do you have to draw a monster and immediately return it to the cup?
31 Related: Suppose an encounter says "Lose 2 sanity and 2 stamina". If you go insane from the "Lose 2 sanity", you'll also lose 2 stamina, right? If you are knocked unconscious from that too, you're devoured, right? If so, it means that the "lose 2 sanity" and "lose 2 stamina" will happen simultaneously. So, can you invoke the "Timing conflicts" rule and take the 2 stamina loss first? (this might be of critical importance in some case. Suppose you have 1 sanity, 1 stamina and your only items are 2 food cards…)