The EBA that all Virgin Australia Cabin Crew (domestic and wet lease
VB crew) are under states that you can have up to 15 overnights a roster (28 day period).
Yes, MEL and SYD are layover destinations for PER crew.
Promotions... Obviously there is Cabin Supervisor but you need to have the experience and skills neccessary etc etc...
All details regarding pay and conditions can be found in the EBA which you can find at Fair Work Australia -
http://www.fwa.gov.au/documents/agre...a/AE872622.pdf