Thanks.Sounds like you got some great advice already and it looks like you are doing a very nice job. I'm just commenting so I can follow your progress and see the finished pictures.
Some in progress pictures. Just a few of the million I took.View attachment 592948View attachment 592949View attachment 592950View attachment 592951View attachment 592952View attachment 592953View attachment 592954View attachment 592955View attachment 592956View attachment 592957
Be sure the copper is not in contact with any concrete. The concrete will corrode the copper.
In your case I'd stay with copper since it's whats there and is a small job, but keep PEX in mind for other plumbing work.
They were there from when the house was built. I hope they did too.I hope you put proper insulation around those copper pipes going through the slab. Concrete will eat up copper, fast...