Hello Steven
Hi, I'm Karl and will be happy to help you today.
First, any email addresses included in a post are removed for security reasons so no one can see what email address was entered on your post making it very hard to follow.
To start off, if you are referring to a Microsoft (office) '365 subscription, it is no longer supported on WIndows 7 so you will not be able to install a current version of '365.
Ignoring the above, if a new version of Office was installed on your wife's computer, there would be nothing to do. It would use to the '2003 Outlook profile to make a copy for the Outlook version being installed so there is something missing from this description or at the very least, something I'm not following. there would be no need to import anything.
As a FYI, uninstalling '2993 would not have removed the Outlook profile and a browser would never be needed in reference to this statement "The message I get is there is no import/export function when 365 is installed to Firefox. "
As far as the browser goes, that would only be used to access Office to downoad / install it using this link
https://account.microsoft.com/services
Also as a FYI, the fact that you have '365 running on one of the Win7 computers means that it is no longer the latest version of Office ''365 but it will continue to run what is installed
Windows 7 end of support and Microsoft 365 Apps