That looks beautifully roomy and secure.
Voice of experience from a hot climate, you're definitely going to want a lot more ventilation over time. I find that unless my coop is in deep, natural shade, I need double or triple the usual recommendation of 1 square foot per adult, standard-sized hen, to keep the temperature under 100F on a 90F day.
For example, this is my brooder, with 16 square feet of permanent, 24/7/365 ventilation and 10 square feet of supplemental ventilation.
And I still had to add the tarp because the flat roof doesn't generate good air flow.
That's a great option!
One of the advantages of having a roomy setup is that you can do things like that -- with facilities inside facilities.