> My recollection was that internals of A/UX emulation were reused to enable the PowerPC transition from Motorola

No, pretty sure this wasn't the case. The RISC LC group used a custom emulator and nanokernel which is not at all similar to A/UX. The RLC couldn't even run A/UX, which was why Apple talked about porting it to OSF/1 for the new Power Macs (which, of course, never happened).