Does anybody know if it is possible to have Federation NPCs as enemies? If not, is it planned anytime in the future? It kind of invalidates my entire idea for a Foundry mission if it's not currently possible.
Depending on the level of mission you could always spawn some Mirror Universe Terrans instead.
Or reskin some Klingons and wonder why your Fed baddies are firing Targs at you.
The first part of his suggestion is the easiest for having Fed style attacks and weapons, but it does add a level restriction. Using Cardasians(True Way) also does the same thing and gives any mob the special attacks used by them. My only issue with using Klingons is they use disrupter tech, which means you will get Fed's who shoot at you with green hued weapons and wield Bat'leths occasionally
It is my hope that eventually we will get a 'blank' template that we can skin, set level, and set weapon type on for both ships and ground units.
Unless it bugs out again, I've been using this reskinning trick to make assimilated NPCs and it's been working pretty well so far, aside from not being able to add appearance bits like the visual components of the Borg and Aegis sets to ships. :c