"that limits lighting to only lights above the mirror and facing down."

Are you referring to the three recessed lights installed above the vanity?

"I thought I wanted a full width mirror...but realize that limits lighting to only lights above the mirror and facing down."

Why? You can install one or more vanity lights above a full-length mirror -- or even on the mirror -- and those lights would not face down.

"The dual mirror approach..."

The drawing assumes three sconces placed equidistant from the edges of the mirrors. Don't assume you can do that; it will depend on the distance between the sink drains and distance between the sink drains and the cabinets to determine whether, with correctly sized mirrors, that's achievable.

"best lighting for applying make-up"

I don't do makeup but with a wide vanity light on my full-width mirror, I don't have a problem seeing my face. And if those cabinets are white, a lot of light will be reflected off them.