AEM was not on its flightplan route. It had clearly been vectored around the ML CTA. My guess is that they had descended to 4,000 ft for the 3900 ft VOR entry. I would assume they asked for descent on first contact with 122.4 after being handed over from 135.7. Where else do you go for a VOR approach? From Tyabb, LTV is closer for an RNAV approach.
JQF had filed in IFR plan to Essendon, via Lacey Colds Monty. It needed a clearance for Essendon. Normal practice would be to ask for traffic and airways clearance on the ground as part of the taxy call. ERSA lists 122.4 as having reception on the ground.