at 36 y.o. spider would have no chance in a five-round, championship/main-event format. he'd keep it competitive in the 1st rd with some clean strikes and defensive skills, but bones’ relentless pressure and will would eventually get to him and he’d get ko’ed or submitted in the 2nd.
I think the wrestling would be the difference. Jones' greco is far too good. As good as Anderson's clinch is, a high level greco clinch is just a different leve of control.
Overeem not fighting in UFC 141?
Not sure yet. There's some drug testing issue going on at the moment. He needs to do a few things, including provide a new urine sample, before they clear him to fight.