I'd remove the two side mirrors and then add the frame. (It's too bad that the light isn't above the mirror instead of touching it.)

-- not an expert

Can you not frame the tops, bottoms, and only the outer edges of the side mirrors?

That’s what I was thinking 🤔

Thank you for your comment. I’ve grown tired of the whole thing so not sure if I’d want to remove the mirrors on the side and frame and center them. I’m answering WD because I couldn’t access a way to comment directly. Thank you both for your responses.

My husband wants the light fixture moved up. Do you think it will make a difference. Is that something that’s hard to do?

You can frame all three mirrors (aka "tri-fold" mirror) together. The mirrormate FAQ page includes an order page just for this. There's a video demonstrating a bi-fold installation. The mirrormate product would hid defects around the perimeter of the mirrors. It would not hide defects in the edges of the mirrors where they meet.

I'm not thrilled that the mirrormate molding sits entirely on a mirror; it does not go around a mirror's edge. I'm not the visible edges of the side mirrors would look acceptable if left exposed underneath mirrormate. Perhaps you could just find a pre-finished molding that could encase the mirrors, cut pieces to fit with a miter saw, and attach the pieces to the mirrors' edges.

Or you could use a peel-and-stick mirror frame around the perimeter of the three mirrors. (In one video, the person wrapped the material around the edge of the mirror. I don't know if the material would stay in place as the edge surface is very narrow.)

"My husband wants the light fixture moved up...Is that something that’s hard to do?"

It depends on what's inside the wall above the mirror.

Thank you very much for your reply😊