After a (very tragic) discovery that basically nobody online sells 2x9 or 2x10 JST connectors, I updated my schematic to use 2 1x10 or 1x9 JST XH connectors for the connections to the OLED display and RPI Zero 2W. I found footprints for all my symbols, finished the schematic, and started the PCB layout process. Turns out that JST sockets are pretty big (relatively speaking). I did some layout work, and now I have a rough sense of where everything will go (see pic below), but I still need to finalize all the positions in CAD so everything is precise and lines up. Although I wanted to keep the PCB as small as I could, something tells me that I might have to make it bigger to allow for more room and spacing for components.