How to move these disposal discharge connections?
OK, If you have to remove the copper piping, start with the trap, the "u" thing, which you need to re install with the new piping. Turn the two brass nuts counterclockwise to remove them from the down pipe and the main drain. The threaded fitting  at the wall should be able to be removed by turning it counterclockwise with a 12 or 14" pipe wrench. The problem is you might not be able to turn it unless you cut the pipe in half, between the 90 and 45 degree bends. It will depend on the clearances. If you can modify this to make it work, it would be to your advantage. Even try calling your appliance person and see about the size of a 1/2 HP disposal. 
This will be tricky if you're not a plumbing person.