Apparently slots are now sorted. The airport seems confident at the start dates posted above.
Hainan have taken a few routes off sale from 1st January due to changes being made. Chicago and Boston have been temporarily removed due to an up gauge to the B787-9, Brussels has been taken off due a an increase to 9 weekly and MAN taken off due to an increase to daily. I don't know why the flights have to be taken off sale to make changes.
All other long haul seems to be on sale so definitely something going on. The 4 routes off sale are some of Hainans biggest profile routes.