I know you said Azula was tentative, but I had to try! cyclicality is an Avatar-based game set in Republic City, where AtLA characters, AUed non-canon characters, and OU non-canon characters are getting yanked into the city for unknown reasons. We've currently got a plot arc just getting warmed up, and there's a Zuko (and a Kiyi) who would love an Azula! . . . Well, you know. Sort of. ;)

It seems to meet your requirements, so thought I'd put it out there!