The part numbering and layout is consistent: D0 (visible LED) is next to IRD0 (IR LED) and Q0 (Phototransistor); D1 is next to IRD1 and Q1 etc. You can follow those back to the pins of the chip on the schematic. I assume you found the schematic here:
While it is not officially supported (and proper operation is not guaranteed), it is possible to connect mode switches for multiple boards together, and some people have done it.
If you connect all of the switches together, it may interfere with reprogramming the modules, and you should also keep in mind that there may be ways to get them “out of sync” such that each button press moves each to the next pattern, but not all of them are on the same pattern.