SgtBloxx

Would it be possible to add the backpack, straps, and belt that this soldier and a bunch of other soldiers wear? Also, would it be possible to add the M1 helmet variant that the Mastermind Mercenary NPCs wear?

Yes, but the chest detail prevents the Freedom Corps symbol from being wearable.

Would it be possible to add the harness/belt set that most Freedom Corps NPCs wear? Making it a belt would allow it to be worn with the Freedom Corps chest symbol.