I've solved the folding problem with the engine installed. A quick release at the rear so the U channel with engine flips up against the seat post. Then it folds normally except it's taller. Works on my Xpect bike.
For quick removal I welded up a wing nut and bolt for the front pivot bolt. To remove: open quick releases by the rear axle. Unplug kill switch wires. Slip throttle cable out of slot at carb. Remove pivot bolt. Lift it off. No tools required. The throttle assembly and seat stay bracket are left attached to the bike. I'll start a thread on it once the quick releases are delivered.