Nice coop!
Separate the feeders rather than having them next to each other. Adding that many birds next spring will max out your space, consider half that many instead. Having a few chicks added each year will even out egg production, unless you are going to eliminate many older birds each year also.
I too use tree branches or saplings as roosts, and some of our birds roost on the rafters, which are 4" fence posts in the old section, and 2"x 8" boards in the newer section. It's all fine. I don't get the oft repeated story about the chickens needing flat boards to roost on, they were tree dwellers and do fine on branches!
Many things work as nest boxes, and don't cost $$$. We have a shelf with plastic milk crates lined up on it, and a slanted roof above, that works fine. there's a board across the front to keep bedding inside. Each crate has a feed bag on the bottom, covered with bedding. Al about 24" above the floor, so still floor space, and six boxes fit across the back of that coop section. I like that there's good air flow through them in summer too.
Mary
