Disguiser
He should not be able to kill people. It's sort of unfair that mafia can kill two people at one night, or possibly even more depending on how many disguisers the mafia has. Instead, he should be like the janitor. Selecting a person who will die that following night will make you be disguised as him. In addition, he should be able to disguise multiple times because of this. This would make it more balanced.
Janitor
The janitor should know the role of the players he sanitizes rather than their last will because sometimes hosts will decide not to enable last wills. In those situations, a janitor will be completely useless. In addition, the janitor is an ineffective role currently, because it's pretty difficult finding out the role that he sanitized. Lets face it, majority of players troll their last wills. If this was added more roles will become useful. For example, the Coroner, who would always find the janitor's bluffs. The spy would also be more useful, because the janitor will have to tell the mafia what roles he sanitized.
Cultist
Killing the main cultist should make converted players go back to their original roles. Otherwise, cultists are pretty overpowered if you ask me.
Mason/Mason Leader
These role ideas are broken. It's unnecessary to have two different roles for the same organization. That's like us having a cultist and a cultist leader in a game, which is highly unnecessary. In my opinion, you should only have one mason in a game, not multiple masons or a mason leader. That mason should technically be the mason leader, carrying all his abilities. He should then have to recruit citizens into his organization. This could be the key to making citizens actually useful for once. Recruited masons will not be able to recruit masons, only the main mason can recruit.
In addition, if the mason leader attempts to recruit a mafia member or a neutral killing role, it will reveal his name as well as all of the masons to the mafia member or neutral killing role. If the mason leader dies, the mason organization does not get disbanded.
Survivor
Lets be honest, the bullet proof vest is a very lame and boring ability. Instead, a survivor should have a different ability called, "Human Shield". If the survivor gets attacked and he used his ability on someone, that player will die instead of him. This would give this role a bigger power and would make it less boring. This ability will also be limited and selecting the player who's killing you as a human shield will get yourself killed.
Executioner
It's rather lame that if you fail your goal, you lose or you become a jester. This just shows that the role is incomplete, especially since it requires the executioner to be turned into another role in order for this role to be useful. So instead of succumbing to that, why not give the executioner two goals instead of one? The executioner should win if he kills a target that is town, or if he lynches all the mafia. That way if he fails his goal, he could still complete the other one.
Vigilante
If the vigilante goes to visit the same person as the mafia, the vigilante should die.