I've not played any of these models yet, but it's fun to play designer.
Thalarian Queller
The Flaming Brand is a good idea but maybe too convoluted to pull off for too little gain? I would much rather have one of their M2E abilities back, like the ability to hand out the "Enchanted Weapons" buff that makes Melee attacks irreducible. That would be similar to "Adversary" in intent and more aligned with their fluff. The range could be short to keep it balanced.
Field Reporter
Yeah, "Don't mind me" would seem perfect here and give them a unique role in Guild .
Pistoleros
I think giving them H2K or Demise Expendable would be two different ways to get more out of this model while still preserving the original intent.
Orderlies
These are supposed to be fast tarpits. Manipulative and/or Deadly Pursuit would fit well I think and make them way more useful.