Also no mixing in Hong Kong, Singapore and Bangkok.
Not quite true. In HKG and BKK the walkways are structured to discourage/prevent inbound and outbound pax/crew mixing, but if you want to have a chat with the replacement crew you are not prevented from doing so. In Singapore I've often passed the crew as I'm on my way from the gate to the beer shop. (Already arranged for the F/O or S/O crew to grab my bag so there'll be no delay in crew transport departure.)