Hi Old Crow--it is obvious that you have spent some time lurking here on BYC! Two more suggestions--I would make the dropping board a bit wider and pull the roost out further from the wall than it appears in the "inside" view. I built my roost 1' out from the wall and made the drop board 2' wide. I am going to move the roost out to 15" and make the board 30" wide. Their poops seem to end up a bit further from the roost than I had planned, and those "squirty cecal poos" are making a mess on the back wall. Hopefully those changes will clean things up a bit.
The other idea regards your feeder--if you want to fill it from the outside, there are several feeder made of 4-6" PVC pipe that are shown here on BYC. The cap could protrude out of the wall, but the feeder would be safe on the inside. I am thinking of trying that also. You will want to keep any feeder and waterers off of the floor (level with back of chickens).
I have a nestbox that is halfway outside my coop, and I love it! Super easy to check for kids and moi. If you make an outside access you will need to latch it also.
Overall I think your ideas are great and can't wait to see the "built" photos.