It’s probably difficult to answer that because the sleeper will never be profitable, end of. It doesn’t matter how you run it, it will never be a profitable service. The problem is that CS need to recover the not inconsiderable investment in the Mk5s, and reduce the subsidy from government if possible (though I doubt they’ll achieve that any time soon).
I believe the answer to your second question is ‘yes’. First of all, the sleeper could make use of existing Scotrail staff in so many areas- guards north of Edinburgh, telesales, drivers on the Fort William route, cleaning staff, service delivery managers etc. There was no need to recruit or train dedicated staff to work in these areas (I appreciate that drivers on the Fort William route are now provided by GBRF)- all Scotrail had to do was train existing staff (who had other turns and other duties) to work the sleeper. In particular, it seems very wasteful having train managers (having to pay for their training which involves considerable route knowledge) at Edinburgh and Dalmuir whose only work is the sleeper to or from Inverness or Fort William- they then have to travel passenger in the opposite direction, whereas Scotrail Fort William and Perth conductors had turns on the conventional day services as well as the sleeper. The only ‘dedicated’ staff which Scotrail employed for the sleeper were the sleeper hosts and the Train Managers who worked south of Edinburgh. Marketing and customer relations too could be handled by Scotrail, with no need for CS to man its own office or recruit staff for these purposes.
As part of Scotrail, the sleeper could also be cross-subsidised from revenue gained from profitable parts of the franchise, such as the Edinburgh-Glasgow shuttles and the Central Belt commuter network (how most successful franchises are run- Greater Anglia being another example which springs to mind). The Caledonian Sleeper franchise as it stands has no profitable services.