1. 4 days on 2 days off (has been also the minimum 36 hrs off at times but new caac regulations are coming in 2019 where it has to be fixed 48 hrs off so ...). can be up and down, or 1 leg and layover, or 2,3 legs with layover, its random, but generally, you sleep around the network mostly for the nights in your 4 days rotation, but not always...
there is loads of layovers in china, a lot to name, but outside china its Singapore, Kuala Lumpur, manila, Bali, I am sure I forgot something..
2. thats personal, most foreigners live in International straits , gated community, very nice. apartment depends on your need, 1 bedroom from 5.000rmb, to 4 bedroom Giant ones for 10-12 k... but this is top of the range, can get half of these prices outside gated communities...
3. yes its possible, not really a dangle, they offered, foreigners refused basically so they stopped offering. apparently they will offer again,
good luck