you could go with a type of plastic pipe called wirsbo it will expand three times it normal size without bursting and then return to its normal size once thawed price is competitive with pex just cant be in direct sun light and normal rings and crimpers will work
if you know the name brand of the valve you can match a trim kit for it.. if you dont then the answer would be no pull the tile down and replace the valve with a Delta to ensure you can get parts for it in the future
