Personally, I'd do two unless 1) the center section will be used for someone to do their makeup (which I assume not by the cabinet configuration or 2) it's small. Otherwise two mirrors with lighting over it is more appropriate.

Jesse Fay thank you, that was my first thought but I keep seeing one mirror in photos so I thought I should ask. Do you have any advice on the size of the mirrors? The sink cabinets are 26 inches. My thought was that something close to that width (but no wider) would work, like 23 inches wide?

If it's rectangle, 23 to 25 is good but if you are doing a an unusual shape, you can slightly over that size you are good because the irregular shape.

If you do 2, I would go oval to stop things from looking off-balance as to the sink vs mirror placement. with one two-light fixture over them.

Otherwise I would do one framed mirror with one 4 light over the center. the light will get to bounce around. the room on a whole and it might help the space look larger.

RL Relocation LLC has some great points. I'm sure you can find some idea on our Houzz page

RL Relocation LLC, I very much appreciate your advice. I especially liked how you specified the number of lights and that the mirror should be framed. My husband doesn't like round or oval mirrors (isn't that weird of him?), so the one larger mirror may be the way that we go. Thank you very much for helping me.

I'd use one large mirror. You get much more and better light that way.

calidesign, do you like the one light fixture in the middle idea too? Or would you expect to see two lights, one over each sink?

Based on the position of the sinks, two mirrors will end up spread wide apart and narrow. The fixture that will fit above may not be very wide either.

Only cause I saw mention of irregular shape --

24 x 36"

Tel Aviv Mirror · More Info

Do sconce / vanity lights have a bit of length so the backplate could cover the hole possibly? buy why not do it now, ...

But black --

https://www.amazon.com/dp/B07K164FMJ/ref=sspa_dk_detail_3?pd_rd_i=B07TW4LXSW&pd_rd_w=T9ZBh&pf_rd_p=cbc856ed-1371-4f23-b89d-d3fb30edf66d&pd_rd_wg=VQvfL&pf_rd_r=EQ9BAP3601V62SP6BA2H&pd_rd_r=6ca0d5d4-eba0-488d-90b5-020b6d1f3b84&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyMFFIVFg2UkQ2VjBJJmVuY3J5cHRlZElkPUEwOTY2ODgzM1VBVlNQMDVCWFpJQyZlbmNyeXB0ZWRBZElkPUEwNTgwMjM3SE9KUDM5V1FVTkcxJndpZGdldE5hbWU9c3BfZGV0YWlsX3RoZW1hdGljJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1

You could do something like this first example, with lighting above. Or two mirrors with one or two sconces between them.

Transitional Bathroom · More Info

Caulder Drive Ensuite · More Info

3 lights [total of 6] look nice over 1 large mirror. 19.7 x 3.5 x 4.3 inches

https://www.amazon.com/dp/B081YVS5KW/ref=sspa_dk_detail_1?pd_rd_i=B07T62FTHQ&pd_rd_w=jivH0&pf_rd_p=cbc856ed-1371-4f23-b89d-d3fb30edf66d&pd_rd_wg=Bfk0H&pf_rd_r=WWEDZHE85J50VQJ78X3Y&pd_rd_r=be7787a9-e79d-495f-b431-2dddb0f32d0a&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFOWjhIUzY0SU9UUjgmZW5jcnlwdGVkSWQ9QTA1NzE1NDExVzdQRlFMMTRDTkFWJmVuY3J5cHRlZEFkSWQ9QTAzMzk0MzMxSllSU01XS1kzUlREJndpZGdldE5hbWU9c3BfZGV0YWlsX3RoZW1hdGljJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1