Not sure if I understood what you wrote fully. But it would really bother me if it wasn’t centered. I’d center everything. Symmetry is very importantly design.

I also feel strongly about a bathroom mirror being centered over the faucet. When we redid our upstairs bathroom we got a slightly wider vanity and had to move the overhead light so it was centered over the faucet and the mirror was also centered over the faucet. I felt by centering both it is more “pleasing to the eye”.

Centered. Not mooshed.

FYI - in your sample photos, if those were medicine cabinets they would not be able to be opened because the faucets are too tall and block the door swinging open. You will need to plan carefully for the mounting height of the medicine cabinet, the height of the faucet, the thickness of the counter and height of vanity. Been there, done that, and had to get a new shorter faucet, even though we thought we did the math corectly!

As long as the mirrors are centered on the sinks I think both options are pleasant.