(3) The spine of the book is a little tricky. I do not have the accurate size yet. Only the size of the front cover plus the flap and the back cover plus the flap will not change. The spine size may be off. So I need to be able to adjust it. Or ask you to be able to adjust it.
My ideas for that are to either:
have both images (the back image on the right side and the front image on the left side) fade to a black color in the forest where they meet in the middle so its easier to just add or take away black from the center.
Or as layers: The front image (1) being the top layer, trees as (3) being the middle layer, and the back image (2) being behind that. So you’d be able to slide the trees behind the front image but in front of the back image. If that makes sense? And then just slide them over if it needs adjusting. So there would be like 4 different layers at least. The main background image, then the back cover illustration, then the spine, then the front illustration.
If that is way too much work though, then just having them both darken to black toward the spine is perfectly fine!
(4) The flaps won’t have anything important. Just an extension of the background. So just dark trees.