Ooof, a bit beyond my capacities to respond cogently! But that said, I don’t think you’d really want to become a “ghost” for very long. Interacting with solid objects is actually pretty useful ...
Indeed. You still need to grab all the money. :-p
Once you’re out of the beam, you will resolidify due to the lack of cancellations (if that’s not a double negative)
However, you still have to get out. Best way I can think of is to irradiate a duplicate of the machine and pass that through the wall of the bank before you go in. However, how do you get it to move throught the wall of the bank given you’ve got no solid to hold onto and nothing to push against?