Technically this excludes all RPF, unless RPF is really about someone's public persona, and thus sort of about a character? (I don't feel very strongly at all about excluding RPF from "fanfic". I just don't read it and so it's not part of my mental definition.)

I can see that it may not be relevant to you whether RPF is excluded or not, and therefore you may not be particularly interested in crafting a definition that addresses those concerns. But I think it's worth pointing out that a definition like that is also going to end up excluding people (me among others) from fandom, to a greater or lesser extent. So if you don't feel strongly about it one way or another, it might be better to come up with a more inclusive definition.