Hi Kate! I'm Grace and I've got at least one who is definitely familiar with James and THEY NEED TO TALK.
This is Remus, obviously, and he's from about six months-ish after the war has ended so, he's a mess. We should totally talk about these two, since things got really not good for a while at the end. Anyway, one of Remus' possessions he brought with him were James' cracked glasses and heaps of guilt so they need to talk. LIKE WOW they need to talk.
As for my other two I have:
itsybitsyspidey Gwen Stacy from Earth-65, aka Spider-Woman aka Spider-Gwen. She's actually kind of like James as you described him. They'd get along well, I think!
sgt_barnesjb Bucky Barnes from the MCU. He's a little gruff and grumpy but he's a good guy with a wicked sense of humor so they might get along? They've both got cool hair? Also have been in battle in wars so they've got some shared life experience even though one had guns and one had wands?