It doesn't quite reach all of your preferences, but if you wanted a slow/medium-paced, backtag friendly game with a little sister who hates your guts castmate, would you be interested in dramadramaduck for Jade? The premise is that characters have access to a multiversal DW community that also reads all of their journal entries because life sucks like that, and there's the chance to use worldhops to visit other worlds and stuff like that. Players have brought up that they want more conflict and events and stuff, so I'm sure the mods wouldn't mind if somehow Jade started getting involved and attacking people and stuff, if you wanted.