Firmware

Apple no longer posts the firmware revisions anymore. You can check this site for what firmware versions are provided by macOS (you may need to look at the older posts as well for some systems):

https://eclecticlight.co/2019/10/08/which-efi-firmware-should-your-mac-be-using-version-4/

Not sure exactly, but you could look here: https://support.apple.com/downloads/macnotebooks