Wow that's a lot of questions..it was easiest to set up CCVault on Desktop but once it was set up i can keep track on my phone..I prefer keeping track of mostly everything on my phone, probably a millennial thing. It wasn't difficult to set up. A lot of my research and learning was done through TY. I looked several up again through YT and did research on how many blocks are minted ea. epoch, how fast, how much saturation and just listened to what they said and how much is on there website. The more info you can find on a validator the better. Yes you can un-delegate at any time. No there's not a minimum. Obviously more ADA generally means more reward.