From there I got to building. I made a couple mathematical errors when constructing, or just screwed up and didn't keep certain clearances in mind. That being said, I was able to salvage it each time.
The bottom horizontal shelf again I fouled up and made it 13" high. This was what I wanted - however I did not account for the thickness of the plywood to line the shelf. I was able to save this (see below). And somehow the top horizontal shelf is only 12 1/2" tall - still large enough for LPs but tighter than I planned. Oops.
I saved the lower most shelf by having the plywood flush with the frame, supported by a 2x6" which is further recessed and running the width of the shelf. I also added some trim vertically on each side to hide the joints on the middle shelf which were unsightly.
After running a belt sander over the whole thing many times, and cutting the 'front door' to the birdhouse so that it is straight, I began to apply paint. I do intend to paint the backsplash but I will leave the shelves themselves (and interior of the birdhouse and top shelf bins) as bare wood as I think it 'feels' better for the records movement. (They are all plastic jacketed anyway).
It barely fit into the work van I used to cart it over to its final destination. I initially (as seen in the original print) did not design it to have two horizontal shelves. Getting it down the stairs was no easy task either. But after all is said and done - its ready to go and in use. Glad to see this thing through.