My suspicion is games like this (I call them "Census" or "Neighborhood" games, since the population of the game is split between two neighborhoods with known Mafia/Town counts) should just start with massclaim.
The strategy at that point
is simple (in the original suggestion, with no abilities and fixed counts; might be different for variable counts):1. Town should lynch from whichever group has a higher ratio of Mafia.
2. Mafia should kill from whichever group has a lower ratio of Mafia.
I ran numbers on these at some point but I don't know what I did with them. Something to add to my scripts.
Mostly it would play like a Vanilla game, just with a restricted pool of lynch targets at any given time (and switching between the two groups as Mafia are lynched).