1 - I think the person who killed the Professor is different to the others, his death appears to be poison, which appears less brutal than the others. I think Andrea's responsible for his. As for the other...I'm suspicious of Vance. He told the others about Didi being "ill"...which is a total fabrication whether he's guilty or not.
2 - One of the gays I'm afraid. Dale.
3 - Shea please. and Bri. and Andrew. and Amanda. wishful thinking?