yes, 'firefox -no-remote -P' is your friend, been doing this for quite some time.
Google is a firefox profile, facebook / whatsapp is another, main browser is another profile
Google is a firefox profile, facebook / whatsapp is another, main browser is another profile
I looked here: https://developer.mozilla.org/en-US/docs/Mozilla/Command_Lin...
It says
Do not accept or send remote commands; implies -new-instance.