Sumlit
San Claudio Bravo
I wouldn't expect Okafor to struggle actually, at least not offensively. His post-moves are already better than most big men in this league and he's got a nice shooting touch. I expect him to get destroyed in defence though.
Okafor was not that great in the NCAA tournament when competition and pressure was higher. I think he'll struggle initially too. It's a big adjustment, and for big men it is even tougher.
You're likely right though, he'll probably struggle a lot more on defense than on offense.