WS2812b Neopixel and nRF52 chips using hardware and software SPI clarification needed for Pixl and MDBT42Q

You keep saying 'via software'. You can't control any neopixels via software on any normal Espruino device - because it needs hardware - either SPI/I2S/etc.

So, is an explanation for I2S (for Neopixels) needed for nRF52 chips in those pages

I don't think so. You can Google it if you want but most people won't care - they just care that it works, and works on any pin.

This still doesn't answer the question as to the number of Neopixel channels(? strings?) for a single device when using Neopixels via software (nRF52).

You can use any pin - so the number of strings is just the number of pins you have.

The note at the Python build files show 1

Yes. There's one hardware SPI, and as many software SPI as you want. But we're not using SPI so it's irrelevant.

the table in #8 could have device by name descriptors

Yeah, it was only left out to make it less of a burden to keep it up to date, but that could be added.