Please define "hang with them".
Do you mean put on a gi and roll with them and not die, beat them in competition?
I see no way Evans could do well in a gi. Does he train daily in a gi? A gi adds so much more variants than no-gi which I'm sure being a MMA fighter is what he focus on. I'm sorry but I just don't see it.
Okay, put it this way. Of the roughly 5000 BJJ BB in the world, I'd bet that Evans would beat at least 1000 of them in a BJJ competition, wearing the gi and all.
Moreover, ask yourself who gave Evans his BB (it was Rolles Gracie), and why do you think you're better qualified than him to decide whether Evans is worthy of a BB or not? Is your knowledge of BJJ really that much better than Rolles' that without ever having rolled with Evans you can decide that Rolles was wrong?