Silver san,

You can use Airport Express as its last train leaves about 130am. I am not sure, however, that CX check-in counter at Hong Kong Airport Express Train station is open at that hour or not, even though the station check-in counter is supposed to allow you to check-in up to 90 minutes prior to departure.

I would suspect Wings lounges stay open as all of the three 'Starlight Express' flights operate on the same day, i.e, Tue, Wed, Thu, Fri only. But do not count on the Elmis Spa to open.