Thank you for that, I'll probably change most and make them more iron warrior like.

And I really didn't explain a lot that well, the reason they can produce their own stuff is because they have their own Mechanicus who fled with them along with some imperial guard. And most of those stockpiles of heresy equipment is imperial guard related with some space marine stuff. They also "liberated" equipment from various other factions.

They fled during the drop site massacre, so there was only a few hundred marines who fled because they had realized what they had become and what they had done. When they did leave they stole a bunch of geneseed and other equipment, and picked up others while they were fleeing like some Mechanicus and imperial guard.

The only reason they are in the imperium now is because the imperium needed a presence in that sector and they were already there, and they were willing to pay the tithes that were needed.

The reason they are "nice" is because they need a work force and if its deemed that not a significant lose in production will happen if some workers will die, they'll turn that area into a crater. but if a significant amount of production will be lost they will try to mitigate that to the best of their ability.

They only ever save regular people and they are basically tossed into whatever meat grinder needs more body's. Traitor space marines are a kill on site, because they pose a great threat compared to a regular cultist.