It’s all on the one ticket. Argh. Oh well. If one doesn’t have lounge access, Canberra is the place to be.
One ticket shouldn’t matter. I’ve had a mix QF, LH RTW fare with QF and UA FF#s in the system.
Flash your QF Gold card at QF Check-in in CBR and the QF lounge in CBR. If necessary, put a points claim in if your QFF number hasn’t been added.
Your bags should be checked through but in SYD, you may have to swing by UA checkin to collect your BP to SFO. There’s the opportunity to ensure your VA number us still in UA’s system and you get lounge access in SYD curtesy of VA WP (and points/SCs).