Portrait!Snape could never give up his acerbity, but he might temper it, as long as Portrait!Remus was there to ease the change.
Yes, that's the lovely dynamic you show, and it makes them so real. Real people don't abruptly, or entirely, change - they accommodate; or at least, really *interesting* and mature "real people" do! And that's what keeps this pairing so evergreen - when a knowledgeable and skillful author recognizes that and ... indulges them. :-) And us!
Compliments for you could never be too lovely or warm. They're always true! I've had to be away from fandom for soooo long but you're one of the authors I always hope to read new fics by when I come back. Yayyy for your productivity! *sends double-chocolate brownies to your Muse*
and Severus & Remus! Maybe they'll get up to some machinations both with other portraits (Dumbledore LOL) and the post-war Hogwarts world... that wd be so much fun!