Here's a wild idea. Thunder said "Say, only Touhou-related RPs or anything goes? Story-focused only or more "gameplay-ish" rounds (such as Mafia Games)? Integrated profiles to use certain OCs every time possible, or creating a new character case-per-case?" It made me think, no matter what, it's going to have some kind of story/exposition anyways, so how would we go about it. What do people think of when they think role play? They think things like Cops and Robbers, Dungeons and Dragons, World of Warcraft, etc generally.
Then, Cejic said "don't create new profiles to do new characters," which lead up to the idea. What if WE don't make new characters, but the Touhou characters make characters. In many stories and plots revolving around Touhou, there's always some sort of gathering taking place, so why not have them gather to try a game that Marisa or someone would've found in the Forest of Magic? We could use a real game name, or we could make our own simplified rendition that takes out dice rolling and complex stats on our part.
Just in case anyone is lost so far, think of it as we're role playing a Touhou character, who is role playing their own character for this. It doesn't have to be just them role playing, there could be moments of Gensokyo world conflicts going on that might perhaps interrupt a session, such as if Suika were to barge in with her sake, or Cirno and Daiyousei eavesdropping and coming in just as it's about to start. They could be a bit of comic relief, or a way of new people joining in throughout the "hopefully long-term" role play.
And technically, who's to say that humans can't join in, which could be a mildly canon or original interpretation of an OC in that sense? This is just an example I'm giving, also inspired by
https://www.youtube.com/watch?v=K8D4Y-FaXQM which is pretty funny.
Overall though, I think it would be good to have two or three independent role play threads going on to try to attract attention to sparking role play in this forum, which I'm sure the administrators would love to see a surge of constant activity if it does succeed.