How to replace/re-engineer leaking fresh water drains

My low water hot and cold drain valves are also leaking. They are in an place where I cannot get to them to replace them. I have been using a rubber stopper (a very inelegant solution) to plug the pipes. Recently I put two sharkbite end plugs on them and will leave the valves in the open position. The plugs can be removed with a removal tool to drain the systems.

I am a little annoyed with the manufacturer who put the valves where then can not be replaced.