I really like and appreciate a lot of this stuff. I'd have to practice it in person to really understand it.
In my experience, a lot of these interesting open guard for MMA defenses don't exist much against people I spar.
The normal scenario is for the grounded man to be on his back, trying to get his feet on the standing man's hips. The standing man doesn't comply, and simply backs up, unwilling to apply pressure against his feet. He may grip fight, trying to grab ankles, back up, kick the lower legs or circle, usually some combination. If not, he will attempt to simply stand over the grounded fighter, not attacking, not engaging. If the grounded fighters moves up, he circles a little. If he shrimps away, he chases.
Then, when the mood strikes him, he throws a lunging overhand right, collapsing heavily into whatever guard position he finds himself in.
The situation of someone simply standing over you, unwilling to rush in to strike but not letting you stand up, is resolved in MMA by the ref finding it boring and forcing the stand up.
For self defense or any fight where the ref isn't concerned about forcing a stand up, it doesn't seem like there is a good alternative so just standing up and attempting to defend whatever strike comes at you. The alternative is the guy jumping on your with an overhand right.