Cop headstart.
— Nightstart. All players may send in night actions.
— The Goonifier's action resolves
after
Cop actions in resolution order such that the conversion can't be detected.
The concept of this setup is to make dethy less solvable by now making one slot at random now the Mafia Goon, thus increasing setup entropy and decreasing the breakingness of the strategy.
You could optionally have the converted Goon be informed of their former sanity if this turns out townsided still, but I'm intrigued to see how this looks.