As far as I can tell brands change all the time and a particular manufacturer will make many brands, some pool store specific. I believe Doughboy is a consistent brand with a good reputation.

Packages - I don't know - Ladder you'll need, also vacuum and hose, pole skimmer, leaf rake if you have trees nearby, skimmer and return, pump and filter. Pool package chemicals you don't need.

Bigger filter - smaller pump yields energy savings and improved water quality. Many AG pools are packaged with oversized pumps and undersized filters. A 24" sand filter with a 2 speed 1HP pump will work well.

I have 1/4" closed cell foam on my walls, it feels soft. Foam will increase the chance of puncturing the liner.

Liners - thicker is usually better - watch out for guage and mil; mil is an actual measurement - higher is thicker, I believe guage is opposite where higher is thinner.

If I did it again, I'd add foam cove, our installer built up insufficient sand in one area of our pool and now I worry it might leak because I can feel the steel lower rail.

Good luck and welcome!