It's the top of the coop
I don't think anything will get thru it up there?
It all comes down to how many chickens you are willing to loose to the predators in your area. I have the exact same coop as you are building but mine is 7X7X7 with 11 hens in it and they get along fine because they can get out in the run all day. The only thing different is I lined the whole run with 1/2 inch mesh hardware cloth. Not cheap but I have not lost a hen where neighbors have lost their whole flock. I used hog rings to secure the hardware cloth to the chain link.
I have 2 big dogs that have access to the back yard 24/7 and i dont even have bunnys in the back yard
dogs Rodasion ridge back and a long wire hair griffon the yoties dont even come close to my house as
both dogs run after them out in the open.
there is a 6ft chain link fence with pool privacy slats all around the entire 1/2 acre rear yard.
since one dog (who is gone) was a digger there is also 6 inch concrete buried around the fence and approx 9 inches up the bottom of the fence
so nothings going to DIG into the yard either.
then around the run there is chicken wire about 18" up the chain link and then UNDER railroad ties over the top of that and then covered with rocks.
so nothing going to dig under there either.
im not real worried about and predators in my back yard.
and also motion detector lights ..
Love the solar fan idea.
If you live at lower elevations in AZ, your "heat-index levels" may be more important than predators. Having a coop in southern NM, I worry about how hot your coop may become inside during summer months.
Can you provide some additional ventilation, above & "below"? Possibly insulate the roof from inside the coop)? Smaller mesh wire at least on the coop openings would prevent wild birds, mice & pack rats from eating your feed. Dogs rarely care about the sleuthing mousie, and can not reach marauding birds (that also can carry disease/parasites).
It would be nice to shade the nest boxes, possibly deterring a build up of heat within the "cubicles". You may have Fried Eggs........