I like these ideas.
There are some versions of TTT that add different roles into the game, like:
Jester - Their goal is to be killed by an inno/det, in order to win their portion of the round. They also replace the person that kills them (inno dies, jester becomes inno). Jester also deals no damage.
Infected - A zombie-like role, where the goal is to infect everyone alive, by punching them to death, in order to win.
Those are the only 2 I remember, but there are more.
This may not have been at all relevant to your suggestion, but I just wanted to add it, because it’s something I would also enjoy. 