My Remus is gay, but quietly so, he hasn't done much about it because for him love bites might equal new werewolf, and it isn't worth the pressure.
He loves the snow, loves to watch it fall, it's beautiful and peaceful.
He loves chocolate (doesn't everybody's Remus?), but in my canon the whole Dementor/Chocolate Frog thing is a coincidence: Remus always just happens to have some chocolate on him, so he gives it to people, and because everybody thinks he's so great at the Dark Arts they say the chocolate must do something real. It's a placebo, aside from the small amount of endorphins chocolate really does produce. If Remus Lupin routinely carried around joints, Harry'd be high for most of PoA.
Remus is a good researcher, but doesn't read for pleasure much, because he doesn't have enough time while he's making ends meet, and because even a scholar gets sick of reading 24 hours a day. Before, Sirius used to read out loud whatever trashy thing he was in the middle of, and as a result Remus has a fondness for Muggle boddice-rippers.
Sirius and Remus were involved before, but after Hogwarts, and it took Sirius a long time to talk Remus into it. They had a few good years, comfortability, shared a flat, but Remus makes Sirius keep it secret from James, and it's disintegrating as Voldemort's 'death' approaches.
Like musesfool, I think Remus lost time after the first fall of Voldemort; while he isn't really Patient Zero, everything I say about him in that ficlet is true in my eyes. Remus uses up all his grief before he comes back and is now determined to stay distant from everybody, Harry included.
When Sirius returns, they shag, because Remus can't turn Sirius down, never could, because he feels guilty, and because he's sure that he isn't going to survive a second war so long-term issues aren't really a problem. When Sirius dies again, Remus just...takes it. What he is really is tired from everybody expecting so many emotions from him that he just doesn't have.
And there's no way in hell he'll be Harry's godfather now. Even if he did want to replace Sirius, which he knows he can't, he doesn't want Harry to get attached to him when he's just going to get killed too in the end.
My Sirius is a lot like most people's Draco. He's a pureblood, rotten childhood, and as a result has a crazy cruel streak. James might harrass somebody for a laugh; Sirius wants to see them bleed. On top of everything, the Sorting Hat tells Sirius point blank that he should be in Slytherin, but Dumbledore has given it special instructions. The knowledge that he's just like the rest of his family really haunts Sirius, and like most people who see themselves in others, Sirius is absolutely merciless to Slytherins, he'll take any excuse to pound one into the dirt. James likes pranks, Remus'll demolish you verbally, but Sirius wants physical violence, the antithesis to Slytherin calculation.
Sirius is one of those effortlessly smart people, but he reads like a fiend, tears through Muggle popular novels like the world was on fire. He hid them under his mattress from his mother when he was at home, and later his flat had so much printed material cluttering it up that it would have smoldered forever if it caught fire. It's the thing he missed most in Azkaban, it's the escape he uses when he's trapped in Grimmauld Place.
By the time school is ending, Sirius is sick of Voldemort and sick of war and doesn't want to take a side either way. He doesn't have the naive idealism and starry-eyed heroism James thrives on, but they're best mates after all and Sirius lets James talk him into being an Auror eventually.
My Sirius is loudly straight and experimentally bisexual. He talks a good game, but hasn't slept with a third the people he says he has. He had a quiet crush on Remus in school, which was not returned and never acted on, but it takes him a few years to realize that he really does want Remus, wants him enough to shoulder through Remus' rejections until the werewolf finally gives in.
His motorcycle is a Triumph, a Cardinal Red 1968 Bonneville, and it's a she, and Sirius rebuilt her and loves her more than anything but Remus and James, and maybe Harry, although Harry is small yet and Sirius isn't sure about this whole godfather thing.
My post-Azkaban Sirius is very confused about the fact that his mind is seventeen, has even regressed a bit from where he was pre-Azkaban, but his body is definately not. He's really on the same emotional maturity level as Harry, and probably makes a much more satisfactory friend than godfather. Sirius knows that Harry isn't James, he does really, but it's easy to slip back into those patterns, easier to pretend that he's got a best mate and he's got Moony like he did before than to sit Harry down and have a real talk about his parents and everything that went wrong.
So he doesn't. He figures Moony'll do it sooner or later, and do a better job anyway. He figures they have time.