pci.hidd is open and documented. It's code is open, it's API is open, and OOP.library system is open too. pci.library is open, in code and in API.
OpenPCI.library is not open: it's API is open.
Anyway, it is not only NON free, it is a wrapper through natives (pci addon cards) libraries (as prometheus.library or other), so even if the OpenPCI.library was used in AROS, it must be some sort of lower level system to manage the pci-bus : in AROS case, the pci.hidd...
Now, it only lacks of devs to create sub-drivers, for scsi or usb or ethernet pci cards... (that's come first in mind)
And yes, hidd's and oop.library could be ported (if anyone wanted to do the 68k port...)
OpenPCI has only drivers for AMIGA PCI BUSSES.
That make a little number of machines (think of A1200-pci, A4000-pci... 1000, 2000, 5000 of each? Now, think of MILLIONS pc's out there with the very same pci bus)
But sure, it can be done.
Appart from that, classic Amiga pci cards (catweasel, delfina-pci/flipper...) should have an AROS driver too!
Adam Olivier