I’m not into Linux/raspberry for so long, but this is how I did most of the job you’re asking for:
Edit your /boot/cmdline.txt and change the following things in the long line of commands you’ll see:
Replace “console=tty1” by “console=tty3” and lots of boot text disappears.
Add “loglevel=3” next to it.nothing that isn’t critical appears anymore.
If you don’t want the default cursor to appear, then also add “vt.global_cursor_default=0”.
save your cmdline.txt again and most of the text is gone, except for one block that shows up between the retropie and ES screens, but don’t yet know how to hide that.
Hope this helps you out. Or at least a tiny bit:-)
Edit* excuse me for reading the question incorrect. I thought you were looking to cleanly startup. However maybe this is a start to make less messages appear anyways..