You better check all your proportions. Will the mirrors be too high because of the narrow light fixture? Will the mirror placement on the small vanity not be ideal because of the electrical outlet?

electrical put in before the vanities is fine, but you must have exact measurements of where the sink will fall. why? because you end up w/what you have.

Mirror over sink, light over mirror. everything should line up or it's going to look like crap. bite the bullet and call back the electrician to fix it. No way around it. someone will have to patch the drywall, prime and paint.

since you're doing this yourself, did you wonder if the light and sink were going to line up? or did you not even think about it?

those lights you posted, what is the length of them? what do your mirrors look like?

if using lights like you have, you may want to lower them. the height you currently have is fine for a light fixture that points downward. What is the distance between the top of the cabinet to the light box? This is why I asked what kind of mirror you're getting. if you're getting one that is 30" tall, how much space does that leave between the top and your light? you don't want a huge gap there.

or, is this the look you want?

Yeah, move the electrical rather than designing around it. Whoever has the long vanity will go nuts trying to get ready with only side lighting on their face. Center light over sink and then add art to the side.

please get your mirrors first before you call the electrician back to fix it. you want to make sure you have the correct spacing w/the light and mirror. don't make another mistake.

round mirror if fine if that's what you want. just hang them and then mark where you want the light.

any other questions you have at the moment?