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I just went through something very recently that was similar, my doctor left a practice and started his own.  His name continued to rank at the old practice (even when the only trace of his name left was in a title tag).

We did a few things:

• Complete separation of GMB pages.  The pages were very specific for the location and the doctor.  We then tied these to specific location pages instead of homepage.
• Checked all citations / NAP out in the web and updated them to the respective doctor's locations.  We had a similar issue, number/ names etc., were not consistent.
• Used SameAs Schema on their contact page to the GMB page (https://schema.org/sameAs) along with the usual Schema for their location / profession.

End result is that depending on the search location and slight variance of the terms, they will both rank in the 3 pack / map.
Our biggest hurdle was one of their GMB pages was deleted and showed them as permanently closed.  This caused a lot of issues for mobile users looking for phone numbers and directions.

We have not made any changes to our client sites for Edge.

Since Edge tends to handle rendering better than previous versions of IE we don't do any conditional formatting for IE.

Now if you are doing something like:

Then I can see where that may try to force Edge to render in ways that the newer version has taken care of.