I am a new DH player, and for my first campaign, I will be GMing. This will also be my first time using this game system. (I am a long-time pen and paper player, though, and the rules here seem reasonably clear to me.) I'd consider my knowledge of 40K and its lore between "advanced" and "expert", and think the DH is hands-down the best setting to run an open-ended "low-fidelity" 40K campaign. (I dislike powergaming and Rogue Trader looks a bit too geared towards no-ceiling character power, but I might be misguided about that.) I like character-heavy and narrative roleplaying, not so much an emphasis on combat. So it's Dark Heresy for me. I currently own all the main rulebooks, the DH GM's book, and the Inquisitor's Handbook.
I need some advice about anticipating character backgrounds and progression. I am still trying to wrap my head around DH's character classes and how they progress through ranks, and how that then applies to the career paths described in the main rulebook and in the subsequent rulebooks. I'm still undecided what "flavor" campaign to run -- Ecclesiarchy, Ordo-focused, Arbite-focused, or what have you -- but am leaning towards a fairly straightforward Ordo Hereticus or Ordo Malleus starting place. Characters will be starting at lowest possible levels, progression-wise and organizationally, with no special advantages or privileges.
So here are my questions (bear with me, and I may have follow-ups):
1) My main priority is giving my characters options for their creation and progression. I don't want my Cleric players to think they get a shitty deal compared to, say, the Adept or Arbitrator characters. Which books will give me the best options for character creation and then progression through ranks? (I am running a game with 5 players, so I am expecting a full range of classes.)
2) Is there an available resource for looking at all character possibilities and progression trees at a glance? (A wiki or otherwise?)
3) Half of my players will be familiar with the 40K universe, and I know at least two will want to become Inquisitors themselves. I've tried to couch their expectations by letting them know that in game, this could represent years of gaming before they became independent Inquisitors. Nonetheless, they will build their characters with this progression in mind. What classes are naturally suited to this trajectory? (More for my reference than for giving them advice.)
4) How likely is it that I will need to consider Ascension, and high-level career paths, in the first year or so of playing (we play twice a month)?
5) I have not looked at 2nd edition DH at all. Should I wait or just plow ahead with 1st? Will 2nd Ed DH "fit" with the expansion books like Inquisitor, etc?
I'm sure I'll have more questions for you, but I'll keep it there for now. Excited to start playing and looking forward to feedback!