| > Supes has his specific weaknesses against Mental/Magical/Energy attacks...|
> Would these 3 beings be odds on favorite to win a solid majority of the time against him in a battle?
I'm not sure any of them would be favorites, per se, but they could certainly win their share of battles. Well, at least two of the three....
| > Would it make ANY difference if they were prepped/not prepped to fight him?|
> Charles Xavier Mental
Professor X with prep and stealth could definitely control Superman....heck, if Poison Ivy can control him for a while with a kiss, then Supes is definitely susceptible to a world-class telepath. That said, if Superman is able to fight off the psi for just a little bit, he could easily rattle Xavier's concentration with just a simple breath.
Strange with prep can beat pretty much anyone, Superman is no exception. That said, I think Supes' 'weakness' to magic is a bit of an overstatement. Everyone has a weakness to magic by its very nature --- Superman is no different. Supes' weakness to magic is no different than, say, Hal Jordan's weakness to it. Superman has enough experience against magic-users that I'd say he could take Strange at least half the time.
| > Extremis IM Tech+Energy|
I'm not sure why you think Superman has a weakness against energy. I think Supes would own any version of Iron Man, even Extremis. The best Tony could do would be to use tech to distract Supes, but for a close look at how this battle would go down, look at how easily Superman has been able to tear through the constructs of the (non-ringed) Cyborg Superman in the past.