After almost a full week of money and effort, my pool filter is operational.
Spent half of Sunday opening the pool. Got to one of the last steps and discover the gasket is busted and needs to be replaced. Ordered a replacement for that, go to install it, they gave me the wrong part. Find the right part on Amazon, 2 days later try to install, and the valve spring is so old and rusted it won't compress at all in order to hammer the pin back in to attach the handle. Order an entire new multi port valve and successfully installed that yesterday. Got the filter up and running after some trial and error, go to put it into backwash mode to drain the water level before I shock and filter the pool, and the backwash hose busts. Pizza went and got a new one today and now finally everything is up and running more or less.
Currently draining the algae swamp.