Not really (I wrote the mouse/display drivers and kernel event queue driver for A/UX 1.x) - A/UX has it's own kernel ADB (and mouse/kbd on top of that) and display drivers, it will happily boot from hard drive, and throw up a non-mac terminal on a Mac display card without executing anything from the Mac ROMs.

The later MacOS running on A/UX ran in a single A/UX (system V) process

So what am I remembering that A/UX needed to boot from ROM?