The current bilateral only has 1 un-allocated slot for Chinese carriers.
2 can be sourced from the old Air China Cargo flights, and, if the bilateral arrangement is a 'use it or loose it' arrangement, then maybe Hainan can 'pinch' the un-used slot from China Eastern for their potential 7th weekly flight.
So, as the rumour is for 4 weekly flights, 4 slots can be sourced at a push, but, we will have to wait and see.