I would consider it to be a larger check-in area with a few comfy seats, free popcorn and so on. I wouldn't want to work there as it is more lounging sofas. There were some board rooms, so perhaps you could use those if pre-arranged.

Not sure on what time is "early", but to be honest I'd just ask for/confirm an early check-in: Ignoring the semi-lounge problem above, the entire casino / resort set-up has almost no seating areas, few cafes and most places didn't even open till 11am. It is designed to make you go and explore and spend money (whether shopping or gambling), not chilling and working. In fact I felt this across Macau in the nearby complexes as well (i.e. Londoner, Venetian, Parisian)