Ehhh, the only plot twist I wanna see is that Syndey has killed her daughter and is Ghostface, stalking all her friends in a psychotic break.
I'll also accept a version where, Clue-style, EVERYONE around her is just offing each other while sequentially dressing up as Ghostface, so in the end they "10 little indians" themselves.
Ghostface, as some mortal regular human looney who has of course somehow infiltrated the targeted friend group, is just silly in a film where everyone is, or at least should be, packing heat. The multiple killer trick worked for the first one to explain some of this, but now it's just ridiculous that folks are not doing a mag dump on him right away.