Will all NPC types (rifleman, custom, builder, medic, fighter pilot ect.) beable to be equiped with weapons and used in a squad? More directly I'd like to know weather Custom NPCs can/will be useable in combat.
Customs will not. At least to the level of being able to fire back. I believe the intention was that each specific NPC class can only use equipment relevant to their class. ie Riflemen can shoot projectile weapons, Meleee Combat Troopers can use NPW, medics can use medical items etc. A Rifleman won;t be able to pick up a medikit and heal you up. At least that is what we know at the moment.