So, Revolutionary Arc. You're right, it is a fic of the Rigel Black Chronicles; none of the characters are genderbent from RBC, so I don't think it needs justification there.
However, it has a very different plot and a different set of characters, and some of the characters who are in both are fundamentally changed--every nomination I've made includes at least one character who's a Rev Arc original (and thus can't really be asked for in the context of RBC) or who is fundamentally changed by Rev Arc such that the sort of fics one might write about them would be fundamentally different depending on which story you accept as your canon.