You misremember, I'm afraid.
Daniel was not a "minor character". He wasn't the main PoV character, that was Johnny, obviously, but Daniel is absolutely the next most major character after Johnny in S1 with his implausibly beautiful wife, his annoying children (one of whom was also a major character (Sam), his car dealership, his useless employees, his huge-ass house, and so on all present from like, episode 2/3 at the latest.
I would say the reboot being Faith The Vampire Killer (it can be changed back to Slayer dramatically later) or something like that would be a good move. Definitely whole "have a different title" idea is a smart one - audiences are much more generous to a show that's a continuation but not claiming to be the exact same show as before.