The pump, water heater, bypass valves, & A/F hose in the M18 are all located together behind a panel in the basement also under the bed area. At least there is a floor between them & the bed. I suppose you could put the pump on some foam rubber or other material to dampen the noise/vibration.
I have given the "failure to retract slide" a bit of thought. On the M18, at least on mine, the shaft of the retraction motor has a flattened end on the motor shaft on the end opposite from the gear train. This is under the Jack knife sofa. I speculated that it might be possible if the problem is electrical or a burned out motor that it might be possible to use a socket on my cordless drill on that motor shaft. I haven't tried it, and I'm not sure the size socket it would/might take or even if it would work. If the problem is in the geartrain or something major is misaligned/askew. I suspect the grear train might have to be disconnected mechanically to allow the slide to be pushed in. A good plan of action from the factory would be welcomed by all of us owners so we would at least know where/how to start if the slide wouldn't go in when out of cell range, in the outback. I very much agree that, "This problem will become horrendously important to one of us in the future". I'm not concerned about major repair instructions, only some suggestions to allow me to get the slide in, should it fail, so I can get on the road. I guess I would look for loose wires, & blown fuses after making sure the battery was charged first.