With respect to the assembly: do yourself a massive favor and let the PCB fab also assemble the LEDs. With a simple bill of materials like this it will add very little cost, it saves you a _lot_ of time, and it might also reduce the chance of component damage from adding too much heat or from accidental ESD strikes. (I don’t know how much these Neopixels can handle, though.)
Of course, having a 5x PCB fab, but 4x+1 assembly would probably double the cost for a single turn of the device.
I would love to hear more about the process of making 5-fold symmetry work for board layout. That sounds maddening to get right.
I think your idea is pretty sound if you connect all but one of the boards in a ring and use a jumper for the control section.
I can only go so many days carefully monitoring diet and minimizing stimulant intake to minimize associated tremors. And I don't have rework microscope, so my eyes would definitely suffer.
Also works for artwork.
From the article:
What's next? ...using PCB assembly...