madrooster talked me out of putting them in First (the difference between F & J was only around $2k) and came up with the cunning plan to burn points instead. First we tried to get two J seats released - that failed. We then scoped out EF and found the J cabin was wide open on all sectors.... still is. Yes, it's a risk - but since we the parents don't have any skin in the game or bums in the seats .... it was a no brainer.
We're inundated with QF and MR points and really need to burn them. We can only take so many holidays - we've already got another London trip booked and ticketed (thanks to madrooster) for April/May BNE-SYD-HND-LHR .... CDG-HKG-BNE. The two long hauls are F with JL and CX, the rest are J with QF ... all on points.
Hopefully, QF really want those 520,000 points, grant the upgrades and the kids get to stretch out. We have a safety net in place as I've also ticked the Premium Economy option as a fall back, this cabin is also wide open.
If they were my parents - they'd be sitting in F, but they are only teenagers, who have had a tremendous run with holidays and premium cabins since they were babies. Interestingly the wife and I had to wait until we were in our late 30's (12 years ago) before we had our first F experience.... which was also the kids first F experience.
Maybe a long haul whY experience will be a good thing as they approach adulthood and life away from the fully funded nest.