Good question. I want his hat.

Apparently higher ranks of the Pickpocket perk will allow you to pickpocket equipped weapons and armor off of NPCs, so as long as the armor hasn't been marked as Unplayable in the GECK, you should be able to get it that way. Also, we don't know if Reverse Pickpocketing is still a thing, so we may also be able to get it that way even without a perk.

if it works like other games you can give followers gear and they will wear it if they find it better.

In Skyrim and Fallout you could not remove the original equipment. yes this system was pretty broken in Skyrim and worked far worse than in Fallout.

Hopefully we can equip NPCs as well. I'd like to give all my settlement guards uniforms while my poor workers wear the same nondescript prison style garbs.

I don't remember.. could we take past companions outfits and wear them.. make them run around in their underwear? I know we could give them stuff to put on.

you can with Graig Boone and Dean Domino. Not sure about FO3 companions, I only uses Sarg 3RL and the supermutant.

Yeah, my bad. For some reason, the word "Companions" didn't actually connect in my brain.