If you are thinking to remove memory chips from another Xbox, make sure you get at least video output. The memory is shared by the GPU and CPU. No display, could mean bad memory.
As for removing them, I use this rule of thumb.
If you want the components, you sacrifice the PCB.
If you want the PCB, you sacrifice the component.
Trying to save both is very difficult, especially with so many solder points.
Personally, I use a propane torch. Others have used a heat gun, both methods destroy the PCB. Heat gun is cleaner.
As for soldering them back on, the best approach has been the solderwick.
Good luck