Welcome to the world of chicken keeping!
I have a few suggestions for you. As other posters have said, they are going to eat that styrofoam if they can reach it. Last summer I had my flock escaping from the run and they would eat the styrofoam around the base of the house. I really couldn't do anything in that case until I decided to clip their feathers so they couldn't fly over the fence. I can't really tell from the picture but, it looks like there isn't any bedding in those nest boxes? You will want to put pine shavings or straw in there so their eggs don't break.
A few years ago, I used to have just styrofoam on my coop ceiling because it was within a larger shed. One night, a weasel chewed through the styrofoam and killed a lot of my birds. I just wanted to point that out to you. You're going to want a ceiling that nothing can chew through or rip off. What we did was purchase enough particleboard and hardware cloth to cover the ceiling. We stapled the hardware cloth to the particle board and attached that to the ceiling, remember, this solution worked because my coop ceiling is flat and it's within a larger shed. This would not work if the coop was outside on its own, the rain would soak and rot the particleboard.
About the feeder and waterer. They will get those extremely messy if they are on the bedding like that. What I do, is I take a milk crate (like what you used for the nest box) and flip it upside down on the coop floor. Make sure it's not on the bedding but rather you move the bedding out of the way and then place the crate on the bare floor. This gives you a sturdy flat area that you can place the waterer onto. The crate is the perfect height. For the feeder, you should hang this one so that the chickens don't knock it off and spill it everywhere. The waterer won't get knocked off because of its weight. If you have a wooden ceiling, you can screw a sturdy screw eye into the ceiling and then take twine and hang the feeder with the twine attached to the screw eye. If you don't have a wooden ceiling, you could hang it by screwing a 10-inch-long 1X2 into the 2X4 at the very end near the nesting box. Then you can make a large loop with twine and hang it from that 1X2.
From the photo, the ventilation opening in the top corner looks like might not have hardware cloth on it. Is it covered? You're going to have to cover that with hardware cloth if it's not.
Other than that, everything looks great! I love how you reused materials, my coop is almost entirely reused materials. It gives the coop such a rugged and woodsy feel.
Goodluck!