[…and not put anything back in the slab except where it has to. This will eliminate the majority of opening up floor to make the repairs.
I agree with Dunbar’s solution. I just would like to take this opportunity to add my comment that I hate the idea of burying plumbing under slabs. I know it’s approved and everyone does it, and I’ve done it (because that’s what the builders want), and the inspectors sign off on it.
But when there’s a leak, and there WILL be leaks, you’ll wish that the pipes were more accessible. There are ways to keep pipes out of slabs, but they are harder and more costly to install.
As with my opinions about garbage disposals (which I think shoud be banned), I know I’m spitting against the wind.