This discussion may contain spoilers!
Clearly it was Mr.toads son. He murdered faith because her and the woodsmen screaming upstairs startled him and he dropped his centipede display ruining it, that is when he went to go ask his dad what the hell was happening.
Tweedledee discovered this and came knocking at toads door to take him away. Toad had just enough time to get his son to escape through the window before getting into a fight with Tweedledee, because he wouldn't say where his son went.
He killed snow because while she was in his room she made a comment about his lady bug collection being very meager.
I predict in the next episode he will kill beauty who is selling him exotic butterflies at night to pay the rent, but she is running out and she doesn't want beast to worry that she is soon to bring on the wrath of this monster.
It is just way too blatant that he is the killer that the game is not even fun anymore.