I've definitely noticed #2 and #3, very annoying! They should both show the same text input (not a straight display clone since they might be different resolutions/ratios)

On a side note, I've noticed some Linux installers don't handle multiple screens well or high resolutions. I think Calamares is a big offender here, it doesn't clone to every display so I end up stuck trying to use my sideways monitor. Or on a 4k screen everything is tiny for no reason, it should just default zoom on high resolution.

I much prefer the installers that are just a regular window on a normal desktop, where you can move it, maximize it, easily access the DPI settings and other system settings, browse the internet while it's installing...