I'm in.
I like the known Don idea if we can get it to work, but as the last game was really nicely balanced I would personally prefer if we tried out a new concept like that in a future Mafia game rather than this one.
My take on the previous game:
Zombie team:
They just got unlucky, I think the setup is fine and they should do much better next game. If we give them more powers they may be way too strong.
Mafia team:
Just a tweak for the Don will be fine.
Normally I would say make him invisible to investigations but if hitman gets killed early they're screwed, and if thief dies no more bullets, so I think that's the biggest risk. I think the Don could be made invisible to investigations while he has no additional powers (except for his recruitment power).
Once a mafia member dies the recruit or Don can take over their role but at 50% efficiency (for both thief and hitman roles, but if hitman misses he doesn't waste a bullet). If a second member dies the Don can take over that role too with the same limitations, however the recruit can only have one role so he is whoever he chose that first time someone died.
Example:
Mafia team at start: Don, Hitman, Thief.
Don recruits: Don, Hitman, Thief, Recruit (no powers).
Thief gets killed: Don, Hitman, Recruit (Thief powers at 50%). (makes no sense for Don to take Thief powers as he would lose investigative invisibility)
Recruit gets killed: Don (Thief powers at 50%), Hitman . (Don is now visible to investigations)
Hitman dies: Don (Hitman powers at 50%, Thief powers at 50%). (Don can choose to be a hitman OR a thief each night, can't do both).
In the previous example when it was just the Don & the Hitman, if the Don was killed next then the Hitman would be Hitman only as he can't become the thief. Only the recruit can take on another role (one time only when first mafia dies), or the Don can (multiple times, whenever a mafia role dies).
SK:
Fine as he is.
Town roles:
Fine all round. Masons voting power is great.
I am not a big fan of known innocents but I think it's necessary with the amount of recruitment and infections in this game. If the cop was hidden and was recruited or infected it would really mess up the balance of the game, so in this case I agree with the cop being known.