The motor mount is pretty simple. Break the top half off if it isn't ripped in half already. There should be metal "ears" off the bottom plate if the last person to change it didn't put it on upside down. Ideally take an air hammer with a chisel bit and hit the ears. It will spin it and break it loose. If no air hammer, then hammer and chisel. If it will not come loose like that, weld a nut to the plate that the rubber was glued to then just put a wrench on it and spin it off.
To reform your belly pan, A heat gun, or even a hair dryer with warm up the plastic enough to reshape it. Good luck getting it back together again.