Beautiful! Hehe, I think it's too late to tell you chickens like to nest 6 to 10 inches above the floor. I think you'll be ok. The chickens will get used to it. Very well done overall, especially from scratch!
The free ranged chickens we had growing up had a big coop, with nest boxes four stacks high. The only nest boxes that were ever used were the ones on the floor, so that's why I built it that way. :) I may be flying in the face of internet opinion, but I'm utilizing some of my life experiences to build this.
BTW, thank you! I can't wait to finish it! I already can tell that the details are going to take forever. I don't mind having a project though, as we're now in egg lockdown... time is starting to crawl.