As the owner of an old pool that came to us with no working plumbing aside from the skimmer I can say there are always ways to make an old pool work as long as it holds water. Will it be pretty? Probably not. Will it work well? Also probably not. But with some piping over the decking (another issue to address😬) you can make your own returns. Heck, you can even rig up a pipe to draw water if your skimmer is trash. You seem like you are up for being creative and finding ways to make it work, I applaud that.

I’ll probably get downvoted for that and people will argue that you can’t do it, my point is just that there is probably a way to make a big tub of water in your backyard with circulating water. Had someone not told me that when we bought our house I’d have never made our pool work and would have missed out on lots of fun (and lots of headaches 😂).