After thinking about this here are my thoughts. Let me know if this makes sense.
If the plumber installs a standard offset flange with an adjustable ring that is 2" offset as at the angle shown in the diagram below this would solve the alignment issues.
The new center would move approximately 1.4" to 10.4" from the wall and 1.4” to the right which would pretty much center the opening between the tub and the vanity. Does that make sense?