Opinion on Vampire Game Mode:
I don't see any disincentive for the town to hunt down the vampire hunter and the anys and subsequently all win as vampire. Perhaps there should be a reason for the town to do so?
Opinion on Rivalry:
Do the two mafia factions share a night chat? Can they target each other?
If they don't share a night chat, AND they can target each other, then town is waaaaaaay too OP, they were OP before, and having 2 maf per maf faction makes the maf even more miserable.
If they do share a night chat, then maybe this might work. The moment they start to get an advantage, the mafia might start to turn on each other, possibly returning the advantage back to the town. Just don't reveal opposing factions' night actions to each other if they can target each other. Although, the town would be heavily reliant on them turning on each other too early, as it might take perfect play on their part to wipe out one faction right away. Unless there are no promotions, in which things become easier for the town to reduce the KPN but still...