Question related to characters still in inactive threads

[Trixie]

I mean to start posting as Sans again, but I think I've run into a snag.

He's currently still in The Usual People with Unusual Talks thread within The Tangled Green, a thread I'm pretty sure has long since been abandoned. Given that Gaster, the only other character within the thread, is currently inactive, would it be okay if I just hop ship and make a new thread there?

Yeah. You just write yourself out. Use some reason that Gaster has vanished and just make a new thread.