I can help with some of these.

1. In the QF scheme, there is no award which allows you to upgrade on BA-operated flights. The only QF upgrade awards are for QF code on QF-operated flights.

3. In the BA scheme, upgrading a WT+ ticket to Club is 40K miles round-trip for LHR-HKG. I have been toying with this very idea myself for the last couple of days.

5. In the BA scheme, the only tickets that can be upgraded with miles are those bought directly from BA. If you have a QF ticket, by definition it will not have been bought directly from BA. However, there are many joint BA/QF fares on the Kangaroo route which you can buy from either carrier, so you might be able to buy it at the same price from BA and then be able to upgrade the BA sectors.

6. You may be confusing the BA and QF schemes here. In the QF scheme, travel in BA WT+ earns 110%. In the BA scheme, travel in WT+ earns 125%. Whether WT+ is worth the extra money depends on how comfortable you would be in normal economy, how much value you place on miles earned, status credits/tier points earned, etc. (I normally take the view that I'd rather go twice, and hang the points.) Historically, though, £299 is a very good fare to HKG and £300 for a round-trip upgrade to WT+ is about as good an offer as one can get.