I went through Home Depot and it was a nightmare. It took since May just to get the cabinets done. I don't have time to wait another week or two for her to respond, so at this point I am on my own. Thanks for your help.

Instead of rushing madly and possibly making a mistake, perhaps you should install a deck-mounted faucet instead. Then you'd only have to make sure now that the water lines and drain pipes were in the proper locations for the sinks (which you know). The Brizo Invari 1.5 GPM Widespread Bathroom Faucet is available (though you'd want to make sure the faucet's reach was sufficient for the sink).

If you're not sure of the proper height of the vanity lights, you could ask the electrician to pull the romex through a hole in the drywall at the expected heights and centered above the sinks, then later install old-work electrical boxes to support the vanity lights.*

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*other commenters may have better ideas of the way wire for future vanity lights

Faucet Height & Backsplash:

-Mount the faucet spout 6-8 inches above the sink rim for comfortable use.

-With a 3cm countertop, a 3-4 inch backsplash is typical. Ensure there’s clearance for faucet installation without crowding.

Single-Handle Faucet Symmetry:

-A single-handle faucet can look clean and modern, especially in a high-ceiling space. Consider centering the faucet carefully to balance the design visually.

Faucet Reach:

-The faucet you’ve chosen (7-inch spout reach) should work fine with an undermount sink and 3cm backsplash. Double-check the distance from the wall to the sink’s inner edge—ideally, the water stream should hit the center of the sink basin.

Mirror Placement:

-Position the mirrors 2-4 inches above the backsplash for proportionate spacing. Vertical mirrors are a great choice for 10-foot ceilings.

-For the vanity light, mount it 75-80 inches from the floor or roughly 3-6 inches above the top of the mirror for even lighting.

Thank you Nick. You are immensely helpful and actually answered my questions!!

Have you chosen the countertop material? In my area (So Cal), stone slabs usually come in 2 cm thickness, not 3 cm. In general, 3 cm is more likely to be used in a kitchen than in a bathroom.

Thanks, coastal vibe. Yes, I have. I knew that some areas do 2cm counters, but want 3cm. I didn't realize though that there is a difference kitchen to bathroom.

There’s a difference in counter height too. And the different spout reaches. You can not get away without doing the specific math for your specific products. You'll have to rip open the wall and redo all if you do.