Gefen: I have no idea. I would assume that a Tinok Shenishba isn’t called a Rasha but I have no real source to say that in this case.
Rav Schachter extrapolates from a Gemara that it’s Assur to bury anyone next to someone even a little more or less righteous than his. He says that’s why each Shul/community has their own cemeteries. We assume that all members of each community for the most part do the same Mitzvos and the same Aveiros, so we bury them together.