You can get rental allowance from day one in HKG. As soon as you move out of hotel. Family can come anytime. Wifey can stay in hotel with you from day one. Kids might be a bit crowding...
No time of to move - however first two weeks in HKG are slow and wifey can househunt with you in tow. Generally advised to not move family over untill simulator training phase is done - but nothing stops you.
Sparrow velocity is proportional to the size of the jet engine sucking it in....