Not as long as you have no issue removing the intake and discharge hoses. IME, these are very stiff hoses and don't like to bend much. Your mileage may vary.

It can be done but after doing it once leaving the pump on the engine, I would never do it again that way. You have to remove all of the bolts to get to the impeller and once you do that, the pump is floating free anyway. Unless you loosen the belt, you will have a hell of time getting the housing and bolts to line up. Once you loosen the belt, you might as well take the pump off. And as others have said, you will want to change the gear lube in the fuel pump. I didn't realize how easy it really is which is why I was also reluctant to remove the pump. Ironically, two days after I changed the pump, we ran shallow, sucked in sand and completely fried the brand new impeller I had installed. I just changed three sea water pumps last week!!