I actually really like this idea. I know a lot of people are sick to death of HP, but it's still a popular fandom, and the only one I'm even in right now. And trio-era games always focus on the trio, so it'd be refreshing to see one that doesn't. I can't commit to playing or anything but I'd be pleased to see this idea take off.
In other words, GO FOR IT! Play up the differences from all the other games out there and you should do fine! People love the lesser-seen characters, so you'd probably get plenty of interest.