More shots of my current setup.
As far as taking apart goes I think my only choice is to cut that 1" copper pipe coming out of the tank. That part should be easy. The hard part is the plan to made that stainless pipe with the remaining 1" copper pipe that goes into the T.
My original plan could still work (unthread from elbow on old tank, install on elbow on new tank, couple with Shark Bite) but I'd like to use the stainless pipe that came with the new tank.