Will be interesting to see what happens, and I agree the choice of cabin fit-out will be highly dependent upon the routes that are chosen.
For the routes, it would be nice to think that any initial order would be used for expansion, rather than just a direct 1-for-1 replacement of the 747. Considering the ERs are only about 13 years old, there is still some life left in them. Additionally, the 333 are around the same age. The non-ER 747s might go, but it would be surprising if the 747 was wound down completely once the first 10 787's arrive
I think it is likely that the 789s would be used for long haul, purely based on the competition (AC, UA, LA). I could see SFO, YVR, BNE-LAX-JFK, MEL-LAX (2nd daily), SYD-SCL (daily) and possibly more DFW as potential long haul. This would surely mean the need for a 3-class cabin. I'd be very surprised if the J product wasn't the new 330 suite (which should go into any refit of the 380, purely for product consistency). Considering the strength of Y+ on long haul, it would have to be installed if the 789 is on long haul. Sadly I think Y will be 3-3-3.
The challenge will be the balance between J/Y+/Y. NZ runs theirs in a 18/21/263, with their angled herringbone. I highly doubt QF would be able to run only 18 J seats on a trans-pac, considering the 747 takes 58/36/270. This might lead to a smaller Y cabin than NZ, with a heavier premium focus?
