I had some time over the holidays, so I made some progress on the PCB. A new footprint for the buttons and for the screen connector, routed everything except for the screen. Next I will need to add a truckload of capacitors for the screen, and bunch of vias for the display signals. I think I will go with SPI, because it's two resistors less, it's faster, and I have the pins for it anyways. The whole PCB is 32x32mm right now.