Too much light? Didn't know it was possible. Good to know!
No, it's not possible for chickens to have too much light in the coop. (unless they get overheated) My coop has 3 windows, and a steel door with full length thermopane window. Lots of natural light. Windows and doors are on S and E side of coop. One of the windows is directly over 3 of the nest boxes, and shines directly in the boxes, as well as providing lots of ventilation in those boxes. The flock much prefers to use those well lit nest boxes instead of the dark secluded boxes below, or the one to the right which does not have a window view! Good lighting actually encourages birds to lay.
I'm wondering if you can build your coop off the back of this shed, while off setting it a bit so it gets some southern exposure. As for the run being on the north, my run wraps around the coop, with 2 bays to the west, one to the north, and one to the south. Not an issue. Proper drainage is the greater issue. I see that you have a slope there. Slope should ensure good drainage. It can also be used as an advantage. Nice space under coop for birds to hang out, and the slope could allow good DL management: start the DL at the top of the slope. The birds would work it down to the bottom of the slope. By the time it reached the bottom, it would be finished and ready for your garden. Biggest issue with trees overhanging, or even as part of the fence line is that predators will use them as a conduit to drop down into your run, or onto your coop roof and kill your flock.