1. Global Explorer (xGLOBxx) RTW is mileage based. One World Explorer (xONEx) is continent based. Global Explorer includes some non-oneworld airlines, thus allowing to visit certain destinations that are not possible on an xONEx (eg PPT, NAN, etc).

2A. It's the same with almost every FFP. Some partner fares are non-earning or reduced earning. FWIW, some believe the open skies changes should soon lead to being able to credit all BA trans-atlantic flights to AA and vice versa. At the moment, however, you need to cross the atlantic either on own metal, another partner such as Iberian (not BA for AAdvantage and not AA for BAEC), or via Canada/Mexico/Caribbean or continental Europe (as the non-earning flights are between USA and UK).

2B. Yup - for premium travellers, QFF is easier to get high status than AAdvantage, but AAdvantage is easier to earn awards. For some status is more important and for others awards are more important. Note that OW Sapphire does have considerable benefits in it's own right.

2C. No, you can redeem AA miles on QF flight numbers and QF points on AA flight numbers. What you can't do is use AA miles to upgrade QF operated flights (regardless of QF or AA flight number) or QF points to upgrade AA operated flights.

3. No. Some have reported needing at least 1 AA flight, although I've booked xONEx's through AA without any AA flights.

4. Anywhere in UK (not just LHR) has high fees if you stopover. If you merely transit the fees are okay. Similarly NRT, FRA, VIE etc. As you are probably aware, Australian airports have high fees especially for international departures.

5. Mileage Monkey indicates which routes may have first, but it may not be fully accurate/up-todate as status changes all the time. Seatcounter provides an indication, but airlines manage inventory on a more sophisticated basis so it is not foolproof. KVS and EF are better, but again may not be 100% accurate in every situation. They should be close enough though.