Though that would mean that passengers to Aberdeen would have to be woken up around 4:45am to be sure of being dressed and out of their berths and on the other train by its 5:30 departure time. Which is a bit on the early side for a lot of people.
0445? More likely 0400 so that passengers can be off by around 0430 before departure of the stock to Fort William at 0450. I'm not sure there would be many takers even if the Scotrail 0530 departure was available for boarding immediately.
Southbound is a bit easier - 2135 Cross Country departure from Aberdeen runs right in front of the sleeper - there would still be a wait for the Fort William portion to arrive.
Arguably, it would be more straightforward to reform the sleeper sets so 10 cars run on the Inverness and Edinburgh portions and 6 cars on the Fort William and Glasgow portions, then offer Aberdeen passengers a choice of railway connections from Edinburgh or Perth depending on their preference.
In operational news, the Aberdeen portion ran empty this morning from Edinburgh so I guess that passengers were woken on arrival in Edinburgh at 0400. Two 73s ran took the coaches onwards. 66+73 on the other two portions.