No, he doesn't have that kind of outside shooting touch or passing game. Roberson is like a fitter version of Ryan Blackwell, maybe a bit bouncier and bit better shot blocker. He has an OK outside shot, but scores most of his baskets around the rim, where he is crafty. But that's about what his build is like - a freshman/sophomore Blackwell, although he seems to be still growing a bit.
To me, Grant looks like he could turn into another John Wallace. That's whose game his game reminds me of. McCullough looks like Charles Smith (Pitt/Knicks) and Roberson, well, maybe he's better than Ryan Blackwell, but Ryan was a borderline Mickey Dees, top 30 player.