1- Settings>Details>Users
5- I don’t think Squeekboard has text prediction yet. (Apologies if that’s not what you’re referring to.)
8- For GNOME apps, there’s a command you can run for each one, which will automatically scale it to the screen every time you open the app.
gsettings set sm.puri.phoc.application:/sm/puri/phoc/application/packagename/ scale-to-fit true ; replace “packagename” with actual name
For non-GNOME apps, I’m not sure. Another option is to rescale everything to 1/2 the current scale, using Settings>Devices>Displays>100%, but that’s not a great solution.
RE battery life, and for your interest, see: Evergreen Battery Test and Another Battery Test
There have been several improvements to the battery meter reading since then.