That's really cute and going to make a nice coop for 4 hens.
I would cut, fit, and screw up some OSB on the inside to add some strength to make it more preditor proof. Coons are strong and determined and wouldn't have any trouble pulling off those wood pieces.
Put up hardware cloth on all the windows, vents, and gaps.
I'd take off the current roof and as suggested, put up plywood or OSB with more of an overhang, then tar paper and then roofing. I wouldn't put in a sunlight with all those branches overhead.
I would also put in a dog proof run and make sure you lock the girls up at night.
Go read the Preditor and Pest section of Forum to read up on what can happen to your little darlings by preditors, whether it's your own dog turned preditor or others.
Do the best you can to protect them.
Can't wait to see updates.