I'm not sure about the stainless as the pipe that is laminated in the hull is probably bronze, I'm not sure. In theory the bonding cable to the anodes should protect the assembly but it is quite the distance to the anodes. I think I would stick to bronze if available but that is more driven by ignorance then anything else.
When I removed the old valve I first removed the hose clamps but I did not try to get the hose off. There is very little room and barb that sits on the valve will rotate inside the hose when rotating the valve. Once the valve is unscrewed it is a bit easier too get the hose off.
I have not yet had the pleasure of removing the bowthruster That is on the list for next year hopefully. Or maybe for the hurricane season when the boat will be stored in Curacao.