Looking at your build thread, you should have the ability to do the water pump. There is not a lot of room, and it does get a bit fiddly at times, but it is possible to do in the car. You don't need to remove the A/C pump from the car, just unbolt it and tie it back out of the way of what you are doing, also you won't have to recharge the A/C system. Remove the alternator, it gives you a lot more room for not a lot of effort. Remove the radiator and fans, and basically remove any other items that will give you a bit more room, including jacking the car and removing the drivers side wheel and splash guards. A little bit of time creating tore room will make the job a LOT easier.
Good Luck