First, I appreciate the responses - thank you!
My goal is to replace all of the plumbing so I can be confident it is sound. I am not at all confident in the current plumbing. I pressure tested it and observed that the suction plumbing leaked down slowly, but the return side lost all pressure in a matter of a few seconds.
Here's a diagram:

It's a lot of concrete, and i'd prefer to cut channels/trenches in it instead of ripping it all up and re-pouring.
Edited to add: the little red triangles are the return jets, blue circles are the skimmers and suction ports, and the small grey rectangle is the current pad for the pump and filter. The long thick black line is a sewer pipe from the house to the sewer main. The Pool is 15'x30', the width of the deck on the top side of the pool is 8', 10' on the right, 16' on the bottom, and 12' on the left. All measurements approximate.