The footage is from the Fox FM Pub choir tactic and was filmed in September 2018 at the Corner Hotel in Richmond.
The Fox FM announcers were all on location for it.
There was also a similar ad for 2Day FM filmed at The Rocks in June featuring Em, Grant and Ed. I’m not sure if it ever aired, but I suspect is was dropped for this campaign as the singing didn’t work as well.
The discrepancy of phone up, then not is simply the order it was filmed as it is present in the Fox ad too.
As for the 2Day and Hit 105 ads, I suspect the breakfast hosts were filmed in front a green screen as the footage of Aaron rich is very similar in both, and the background clearly matches the rest of the shoot. They potentially filmed that shot with space to add people in if lineups changed.