In building my BOM (I'll add a link to Octopart and enter the parts here at some later time), I found that [1] I was unable to find a plug whose footprint matched the one I'd placed, and [2] I'd been using altogether the wrong kind of plug for my Qwiic connectors anywhere I'd been using them. Those problems are now corrected, at least here (as of this writing I haven't even looked at my other designs).

I've also managed to cram the components together enough that I could turn the MIC and SPKR headers around, leaving plenty of open space.

There are probably a few other improvements I can make here, mostly in the interest of shortening traces, but on the whole I think I'm close to ready to start making the Gerber and Centroid files, toward having a prototype made.

With any luck, I'll be able to order those prototypes around the start of October.

An interesting note about the BOM: the Spin Semiconductor FV-1, which is the heart of the project, accounts for more than half the cost of components ($14.54 out of $28.77 as of this writing).