The answer really depends on where the light source is relative to the object you want lighted. A good surface mount light behind the individual will provide adequate but noit great lighting because some light will be reflected from the mirror onto the face. The optimal solution would be a combination of sconces or over mirror lights in combination light placed behind.

You’re going to need a whole lot of lamps. I hope there are extra outlets. These rooms will be virtually unusable after dark. The ceiling height ensures a dim barely lit space. Unless you can get some wall sconces added, down low. Only there aren’t enough walls. The foyer is the real problem. Especially for a home for 55+. It’s a hazard where you can’t see. We need twice the lumens as young eyes as we age. A single pendant is not going to cut it. I’m not even going to start in on the fact that nothing about it is built as an accessible retirement home. If you ever need a walker or chair, you’re out of luck.

IMo the size needs to light the space and usually the size that works with the island zMore important is the actul light bulbs you choose since a walk in closet lighting should be as close to natural daylight as possible so a fiture that is LED 4000k bulbs id the first item since the island is so naroow I woud porobably look at linear fixtures almost as long as the island wouldbe very cool. Or go big in proportion to the space after the storage is decided. Make sure there are no shadows anywhere too .

I would put it right where the current light is. It looks like light is centered on ceiling of the entire width of space right now. That’s where I’d leave it. Especially if the new light base against ceiling is larger than current light base is. Looking at entry door, you have door on left, upper window on right of wall & looking at stairs you have stairs on left, half wall on right & another ceiling light farther back on stair landing. My thought is if new light is centered on door or top of stairs it won’t look centered or lined up with anything - may turn out looking like a random placement. It looks like it’ll fill more air space than your current light so it’ll draw the eye much more too. When you build your new entrance will be the time to move wiring if needed.