Please be aware that at least one of these settings will log you out of all your accounts (I suspect it may be the one related to fingerprinting, though I am not certain). If, as I am, you are signed into 10-20 essential accounts, including work accounts, it is going to be very difficult to get your browser back into its prior 'ready to use' startup, state, even after you have reversed some of the settings outlined here.

There are easier ways of getting a 'fresh start' for cookies and logins on Firefox than this. It has taken me an hour to undo some of the damage done by even timid experimentation with these settings.

Sadly, this experiment logged me out of a YouTube-only Google account that I was able to make before Google closed the loophole that allowed you to make a YouTube-based account without the need for any email address or phone number. Re-authenticating at login for this account now requires that you supply an existing email address and phone number, so the utility of that particular account has gone forever.