I'm glad you provided this example with the multi light fixture. Note the shadows. There should be direct balanced lighting to the subject in front of the mirror. Otherwise the shadowing effect may be distracting. Perhaps a ceiling canned spot light in front of the toilet, and then balanced light or lighting for the vanity.

There is an overhead light from the bathroom fan right in front of the vanity- that would be sufficient, correct?

Which would be better overall?

i would center it over the vanity. good luck!

vanity. like the pics

or do a large room light like this one

Lower the picture so that it’s top is lev with the top of the niche. A mid-wall sconce and a matching sconce on the side walls would give even lighting for make-up and shaving.

The lights should be centered on/over the sink/mirror area of the vanity. Lighting is necessary to the person using the mirror, not a person using a toilet. For the toilet, a ceiling fixture and reflected light is sufficient. If you put a long decorative light over the vanity, as shown, you will need a good ceiling fixture as well to fill the shadowed areas with light.