I also used Frequent Flyer, found the same availability and I tried to get seats on the A380 on a AONE5. You will get waitlisted. Unfortunately you will never get confirmed. They ONLY book R in the A380 (according to BA, QF and AA). Possibly because the "R" fare is relatively new (and most certainly for QF) they show A and F too in the system. Could be a glitch, could be necessary in case of an aircraft change. Don't know. What I do know: no way you are getting on an A380 in first with an AONEx.

When I asked there was no information about possible surcharges like with SQ. You cannot fly their A380 on a First class RTW either.