I may be answering a slightly different question, but I feel that Amari Williams has most potential to make it at some point. He may not be the closest at this point, I don't know, he may be that too, but that is harder to judge for me.
Amari Williams has some of those "can't teach" traits that none of these other guys have. He has the size and length of course, but he has really good hands, really good vision, and handles the ball like a guard. He also disappears and seems completely lost out there at times, maybe even most of the time.
I am not sure what the deal is with him and his "disappearances", but with those can't teach natural tools, I see him as well worth some developmental investment.
RJ Luis, I am still not sure about. I don't believe that I have ever seen him play so don't have a sense for him. All the other guys seem to be exactly what appear to be, fringe NBA players at best without a whole lot of ceiling. So to the bonus question, I have no idea. They all seem equally underwhelming to me.