From what I remember reading when wondering about this, it will require quite a bit of wiring work to adapt an HFM M104 engine and/or transmission onto a CIS M103 car.

Since you have an entire running donor car, I believe it should be doable if you are up to it.

No idea about the SLS pump, as mentioned body parts will swap over, same with the brakes as long as you swap over the other parts needed for clearance like the front lower control arms.