Cedar siding outside is fine. Cedar shavings in the coop is not fine.
That's a tiny coop, and very short too. Designed for three hens? More really won't fit comfortably.
I think that it needs at least roof support at 24" centers, depending on your roofing choice. 16" centers given that it's very small framing already.
In snow country, always build with snow load in mind! Look at what's needed for other buildings where you live, and build strong enough!
@amk122284 , I hope you replaced the window screening with hardware cloth secured to the framing of your building. Raccoons get through screens with no problem.
Mary