I was under the impression you were travelling alone with the children but obviously I was mistaken...perhaps you could take the chance after all..
The VJ connection outward with 3 hours plus connection looks ideal to me.plus an O/N in SYD on the way back.
ANA award site showed no availibility on points for HK /AUK but you could pay 35000 HKD per adult per seat for business class or get an extra 6 inches of leg room in PE at only 17000 HKD per seat.
Another way if points are no problem as you indicated, would be to use SIA..
Only 33000 HKD for business or points seats available at 620000 per seat.
Best of luck with it.