1.) Is attacking with a wielded weapon and a servo arm dual wielding?
2.) Servo harness has 2 arms, so does that mean that I can put a breaching augger on one and use the normal servo arm for the other?
3.) Say, I use dual attack with Omnissiah axe and Breaching Augger, then reaction attack with servo arm. Is that valid?
4.) Where do I find stats on more cybernetics other than Core rulebook and Rites of Battles? Since I've seen people talking about bionics I've never heard of before.
5.) I also caught wind that the Breaching Augger deals 2d10 instead of 4d10. Is this right, or is the book right?
6.) The Artificer Armor Signature Wargear at rank 4- do I need Hero to wear it?
7.) Do I have to requisition Servo Arms/Harnesses and Breaching Augur every deployment?
Meant to reply to this after class last night, but ended up forgetting.
1. Was going to say 'yes - except' like decessor, but the rules state servo arms may be used either as a standard attack or reaction attack and a servo arm may only make 1 attack per round (pg. 177). So you cannot use a servo arm as a multiple attack action (which isn't a standard attack).
2. An Augur may be attached to a servo harness. As it is large enough to be a servitor limb it should take up at least one servo arm. I'm sure you can add it as an extra arm (harnesses being complicated as they are) but I'd make my techmarine sig wargear it or have him replace an already available arm, tool or servo (why create another arm socket you'll only use for one mission?). Any modifications should require a tech-use test, failures should give penalties to its use (up to GM) and great successes could give some small bonuses.
3. I don't like the idea of using an Augur with multiple attack actions. I would rule it may only be used as a standard attack (it is too much like a servo arm in its own harness or on a servo harness), just seems more sensible than swinging a giant vibrating drill in 360 arcs to hit someone 3 times. If you absolutely wanted to play exactly according to written rules, then your example is valid (as the Augur is technically not a servo arm, although it is attached to a servo harness like one). The game does state some things are impossible and common sense should be applied, personnaly I feel common sense says the augur should work like a servo arm.
4. First Founding is the only location I know which has DW specific cybernetics. DH and RT have some cybernetics in them not in the DW books, but I would only allow just a few of those options to a space marine.
5. Errata weapon damage is a good stop-gap. Scaling DH rules to space marines gets rediculous pretty quickly. Low UT and ARM has weapons like the orginal bolter stats being devastating to everyone, once UT and ARM gets really high the only thing which can hurt you are anti-tank weapons. Personnaly I'd like to see armour rules revamped. The errata weapons fix some of these scaling issues. As for the Augur, its supposed to be used to breach walls, not smack gretchin. Its change was probably to make it less desirable to min/max munchkins.
6. No you do not, you built it yourself, once you got it you can put it on. I would not allow it to have any armour histories though, similar to Mk 8 armour rules. You just finished building it pretty much from scratch, its not been in battle or suffered numerous repairs etc. which gives other armours their personalities.
7. You get a servo arm as a tech marine, you always have it. You have to requesition or sig wargear a servo harness unless you take the Servo-harness Integration talent. With the talent you get the harness system, but not a billion arms pre-attached. Anything over the basic stuff I'd have elite advances with tech use skills to atach them (obiviously your first arm is attached from the start, perhaps give up to 500 xp worth of req  for extra arms for free when you buy the skill). Augur you need to requesition each mission unless you sig wargear the item. Then you can take it whenever you want to.