Regarding Warne vs. Viv, this is one battle of the egos I would pay to see. Just to see Warne's mindgames vs. Richards' swagger.
I envision this as either Warne getting Richard's wicket early through a miscued shot or stumping, or Richards carting Warne around the park. But overall, I think Richards' sharp reflexes and fearlessness in getting to the pitch of the ball would give him a slight 6/10 advantage over Warne. But what a battle it would be.