You can install whatever version of Firefox you want. But older versions may have problems accessing the web.

You can use sync to share passwords, bookmarks, and history. Anything else may not be compatible between different browser versions or computer systems.

https://support.mozilla.org/en-US/kb/how-do-i-set-sync-my-computer Sync your bookmarks, history, passwords, add-ons and open tabs with another copy of Firefox. Learn how to set up Sync.

https://support.mozilla.org/en-US/kb/how-do-i-choose-what-types-information-sync-firefox We'll show you how to choose which types of information (bookmarks, history, add-ons, and passwords) to share across all your devices through Firefox Sync.

https://support.mozilla.org/en-US/kb/firefox-sync-troubleshooting-and-tips

https://support.mozilla.org/en-US/kb/sync-firefox-bookmarks-and-browsing-history-iOS Sync your passwords, history, tabs and other browsing information across your iOS, Android and desktop computers with Firefox Accounts.

Thank you for your response but password, bookmarks and history are not the instant problem...

I can install the same exact version of FF to all four machines. Then is it possible to copy over all Config and Policies settings to the other machines ?

Yes. Sync can do much of that for you. If there is something else you can use a thumb drive.

Type about:support<enter> in the address bar.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder

Linux: Under the page logo on the left side, you will see Application Basics. Under this find Profile Directory. To its right press the button Open Directory.

Warning ! ! Only Copy the files you are told. We will avoid anything that might cause problems. Here is the list of files;

cookies: cookies.sqlite Do not bother. Cookies will be created when you return to the website. However, you will have to log in everywhere. And you may lose any settings that websites store on your computer.

extensions(add-ons, themes): it would be better to download them fresh. If you need to remember what add-ons you had, open the extensions sub-folder and look at the .xpi files

logins.json and key3.db [v58+]key4.db : These are the password files. Copy Both !

persdict.dat : custom dictionary - words you added to the dictionary

mimeTypes.rdf [v55+]handlers.json : What to do with what type of file.

places.sqlite : History and Bookmarks.

prefs.js : Your settings. Note: If you were having problems, this could be contaminated.

cert8.db [v58+]cert9.db and possibly cert_override.txt : Stores all your security certificate settings and any SSL certificates you have imported into Firefox. If removed, the cert8.db, cert9.db file will be replaced.

search.json.mozlz4 : file stores the user-installed search engines that are available in the Firefox v47+

search.sqlite file and searchplugins folder store the search engines that are available in the Firefox Search bar before Firefox v47

Copy these files from the old to the new. You may get a message that the files already exist. Choose to over-write for each file.

Please move on to my posted question about floating videos. Several posts and no responses. Have posted several times on this topic over several years. NOTHING works ! If this problem is not solvable via FF fine, I'll delete it. If this problem cannot be solved by anyone within your organization, fine. Just tell me such.

Am so sick of floating videos, first browser I find from here out that stops them is in and FF is out. Which direction do I go ?

Thank you for your assistance on cloning settings to my server and other machines...