Report about my experience regarding the CX/QR return segments:
Have checked in CX online and QR online while in Australia (48 or 36 hours prior to my first departure segment) and could print out at home all BPs CX SYDHKG and HKGDOH and QR DOHFRA.
The reprint of the CX BPs by the CX checkin counter at Sydney International had the advantage of being given lounge invitations for SYD (QF Biz lounge) and HKG (any of the crowded CX lounges- both not needed at the end...) and an Express Pass for SYD immigration/security. The cost of stopping by the CX counter has been 5 minutes, mostly absorbed by passport check.
Cheers,
juan516.