To me, the primary keys are Frankie's speed and his takedown defense—both of which will have to be top-notch against Maynard, who no doubt will look to take the fight to the ground.
Frankie needs the speed—that's hand speed and movement, by the way—to not only keep Maynard off-balance, but to also avoid any shots Gray wants to throw, and Gray won't take throwing shots out of the question.
He'll need to be quick landing on Gray inside the pocket, and he'll equally need to be quick in throwing effective shots on the outside.
As for the takedown defense, we all know what happens if the fight hits the second or third round, and Frankie hasn't been taken down—not even by a trip takedown.
If Maynard can't take Edgar down, he'll have to resort to his Boxing, and I'm not sold on his Boxing being good enough to where Maynard can KO Edgar.
I won't be surprised if Edgar is the one who takes Maynard down or vice versa, and I don't see it as a key in this fight because everyone expects that this is going to be nothing more than a twenty-five minute Wrestling match.
One other key, which isn't really primary but can be considered as such, is Edgar's submission game.
People see he's a Wrestler and automatically assume that he's only going to wrestle.
That would make sense if he didn't train with Renzo Gracie and Ricardo Almeida, but he does train with Gracie and Almeida is responsible for the fact that Edgar does know submissions.
I say if Maynard wants to take Edgar down and he does get that takedown, great, but he's still dealing with a guy that knows some pretty painfully disgusting Jiu-Jitsu.
Take him down at your own risk, Maynard—just try to watch out, or Edgar might choke you out.