As stated earlier, you'll need to switch out at least the rear wheel. Even the manic mechanic sprocket adapters won't work with that many spokes.
I would highly advise avoiding the use of anything between your bike frame and motor mounts. The rubber won't do much, and it's much better to have a flush metal on metal contact. I'm not sure but to me It looks to me like you won't have much problem using a manic mechanic front motor mount and jimmying something for the rear mount.
As for mounting the gas tank, I don't think extra wide mounts will do it. My bike (fito modena GT) also has a really large top tube. I just cut up a belt and drilled holes to make it work, along with foam mounting tape underneath the tank. It has a little wiggle to it but it gets the job done.