GIGO is garbage in, garbage out. Don't expect a nice outcome if you start with shit inputs.

Still, I'd argue that a home raised pig on such a diet would be immensely better than a factory farmed one. I'm just not a perfectionist, as we don't live in a perfect world.

Also, traditionally raised pigs here had no lysine supplements but they managed somehow... for a few thousand years... Sorry it's in Bulgarian, use google translate: https://bg.wikipedia.org/wiki/%D0%98%D0%B7%D1%82%D0%BE%D1%87%D0%BD%D0%BE-%D0%B1%D0%B0%D0%BB%D0%BA%D0%B0%D0%BD%D1%81%D0%BA%D0%B0_%D1%81%D0%B2%D0%B8%D0%BD%D1%8F

If you do have whey though, that's great. Our grandparents of course raised "yard pigs" and their daily food was whatever grains they had soaked with whey. Another thing was the pumpkin. Here pumpkins were not eaten by people until very recently, I'd say 60-80 years ago. They were grown as a well storing fodder crop. This kind:

Re: yard hay, mow it, dump the bucket on the front lawn and spread it around to dry. Turn in a couple of days. Has to be thoroughly dry. And you'll need a hay shed ;) YT videos of small scale haymaking would help.