I agree with sunflour! And 10'x10' will be awful to crawl under. No way! Also, I would be using standard dimensions for plywood and siding, so 4'x8' building units instead. Also, a square coop isn't as useful as rectangular. Use the money spent on flooring to roof more or the run area instead, and plant trees and shrubs for more shade around the coop.
Looks like you are planning a nice setup!
There is no "wrong" but I agree with sunflour as well. I would not want to crawl under the coop to retrieve a chicken and it's possible you may have someone(s) decide to start laying eggs under there as well.
What I'd do again: Have a walk-in coop, makes it easier on my old bones. Mine is approx. 8'x12', for 7 chickens, but I would like a bit more room to set up a small separate area to hold a broody, a cockerel, or even an injured chicken (not sick) if ever needed. We've had a ton of rain so having 12'x12' of run covered (metal) and then another 5'x12' just covered with hardware cloth on top has been nice. The run stays fairly dry except when the wind is really blowing too. The uncovered part, they love when it's not raining. Mine too do not like a lot of direct sunlight (which surprised me). Early morning, they want sun when its in the 20s, but as the day warms they get in shadier areas.
Roosting: That one is hard. I like the ladder roost that I have. It hinges, so I can lift it up and attach it to the ceiling so I can walk under it to clean etc., I have poop tubs with pdz so sifting the nights droppings is easy and quick. The ladder does take up quite a bit of space, so if I ever built again, I would probably put in one long roosting pole/bar and poop boards underneath.
I also have cameras in the coop/run. Even though I'm mostly home and can look at them through the window, the camera lets me see inside the coop and I can see whats going on.
Something to consider: I really didn't think about wind blocks outside. I focused more on the coop with proper ventilation and being free of drafts. The coop is on the NW side and I get a lot of cold wind from that side, so I temporarily add some wind block on one side, but hopefully will come up with a better plan for next winter.
Always go bigger. I think I will always wish for more room.
Have fun and enjoy!