Basically all of this has been addressed before in this thread if you would read it.
Biyombo is the son of an African diplomat or something so his birth certificate is legit.
Sene couldn't receive playing time in a lesser division of basketball at the same age that Biyombo is playing a decent amount of minutes in and has produced fairly well in.
Biyombo isn't necessarily a PF.....he has the length and athleticism to play C similar to Ben Wallace. And yes, we know that his offensive game isn't developed. If it was, he'd be a top 2 pick and you'd be telling us we need to trade up to get him. He's a prospect with great potential BUT could still play right now. And regarding your draftexpress article....the same guy who evaluated Sene said that Biyombo is better.
So basically what we know about Biyombo is that he's athletic, he can play interior defense (oh hey, we need that remember) and that he works hard. He's not gonna be some lazy bum that doesn't try to advance his game. Hell, he's 18-19 years old and already playing against grown men and producing. I wouldn't be worried about him at all.
Also, I'm a Klay Thompson fan....but him at #12 is just plain ridiculous. I mean, c'mon.