If WWE are really set on sticking with the underground thing (they'd be better off just cutting their losses and dropping it altogether imo) then they need to remove Shane McMahon immediately and keep him as far away from the thing as possible. I know that he's supposed to be the "cool" McMahon and everything but the reality is that he's a fifty year old man who's quite possibly the most uncool human-being to ever breathe air!
If they seriously want to try and make it at least vaguely credible then why not go get Shamrock involved? He was a proven legit fighter, he'd cost WWE comparative buttons, it'd be a cool moment for older fans and him running a fight club would make more sense storyline wise.