
I agree with what others have said: From a fanfiction point of view, it's all well and good. But from a cooperative roleplaying point of view, I can see it being difficult finding a whole group of people willing to be relegated to "secondary character" status by default. After all, in RP, everyone is essentially the main character in their own story.
What I might suggest is to keep your Fiction!Character and your RP!Character thematically connected, but ultimately separate. Perhaps they're largely the same person in terms of background story elements, personality traits, etc. However, they wouldn't necessarily share the same continuity and, obviously, the RP version of the character might be in need of some tweaking to be more RP compatible.
That way, you could use RP to develop your character in a more interactive environment and glean some inspiration for your storylines, but have the flexibility of being able to use that however you want in the separate Fiction!Character's continuity without stepping on anyone's toes, RP wise.
Just my two cents!
What I might suggest is to keep your Fiction!Character and your RP!Character thematically connected, but ultimately separate. Perhaps they're largely the same person in terms of background story elements, personality traits, etc. However, they wouldn't necessarily share the same continuity and, obviously, the RP version of the character might be in need of some tweaking to be more RP compatible.
That way, you could use RP to develop your character in a more interactive environment and glean some inspiration for your storylines, but have the flexibility of being able to use that however you want in the separate Fiction!Character's continuity without stepping on anyone's toes, RP wise.
Just my two cents!