You won't need that many nest boxes. They'll mostly all lay eggs in the same box so you could increase the floor space a bit by taking out one partition and the front ledge.
Given you're going to have to repair the legs take the opportunity to get the coop well above ground height. At the current height any rodents can get busy gnawing their way in unseen. A couple of foot off the ground is good, more if you can make it stable. Heavy legs fixed to the outside running up the coop walls a couple of feet could work well. You would of course have to add a ramp, but if it's high enough for the hens to get under you've got a weather shelter thrown in.