I don’t think Rumpel and Charming can and will be friends. Charming dislike Rumpel or despise him with reason.
He rejects this new family because I think it’s a bit too much for him to take,
Not really for me. He reject it because he is selfish. It’s not too much for him to take. After being alone for so long, don’t you think he would happily accept to be part of the family? Yet he don’t. Or maybe it’s because he really is stupid. After all scheming doesn’t necessarily imply intelligence.