How much support do aliases have for AFP? They can link to AFP shares, right?
On the Pi side, you could have an AFP share for every USB stick attached. You could then augment that that with another share containing aliases to each of those USB stick AFP shares. This would be pretty good already, though you could also add some MacOS-side code to watch that directory and mount new aliases when they appear.
There’s no SCSI in that design, so it’s not necessarily relevant to this topic, but I think it’s better than a a SCSI solution, which could run into issues with volume sizes dependent on the model of Mac in question.
A bit of a common sense check on *IPL0 on the GLU, since we also have the BBU connecting to *IPL0 via a +5V pull-up resistor, this value should only ever be high-impedance or GND, correct? If so, that common sense can certainly take a chunk out of the complexity of the OE equations. That just leaves FCLK.oe as the exceedingly complex OE equation to be dealt with.