In both cases they can't be combined on the same PNR (even purchased/purchased). In that case they can certainly be linked for IRROPS. I see no reason why this shouldn't be possible when one is award,and I would suggest calling back. This is an assumption on my part, but I don't see why IRROP protection would not be possible in this case.
How much IRROP protection does linking the PNRs provide, AA to AA, or AA to another carrier? I had the impression that if you have separate PNRs and miss a connection, transferring you to another flight was at the discretion of the carrier, particularly for international flights that don't have the same standby flexibility as domestic US flights.