I really like your concept. If you're setting this in the timeline after changes and still want to use the Red Court in my campaign I found a way around their complete extermination. Since all of the Red Court wasn't present at the ritual in Chitchinitza I had a single red court vampire that had finished his first feeding in Brazil only seconds after Susan had completed the transformation. He's the last of his kind but was an initiate half-vampire for a while (still younger than Susan however at only around six years). He's the last of his kind since the ritual only killed all those that had turned before Susan. In the same vein as the black court being beaten and in hiding he's creating a small cadre of vampires in secret. It's a good plot device if you like the Red Court, PC's want to play them, and you want to recreate a power structure for them.