Originally Posted by MSPeconomist

My opinion is no. If your SQ and DL flights are on the same ticket (and perhaps if they're not), you can get a boarding pass for the DL flight when you check in with SQ. However, once you go landside (for dinner?), you will not be able to get through passport control to return to airside without reporting to the DL checkin counter after it opens, where they will ask a few security questions and do something to your boarding pass or generate a new one so that you will be able to go through passport control and return to airside.

If you want to spend the night at the transit hotel, you will need to have dinner also at SIN airside. Also note that the checkin area in T1 is not at all a good, interesting, or comfortable place to spend time.

In your situation, I would probably book the transit hotel for the night and plan to spend the afternoon and evening before your DL flight exploring the SIN airport, including the pool, slides, butterfly cage, sunflower and cactus gardens, koi ponds, movie theater, etc. T1, T2, and T3 are all connected airside 24/7 even though the little trains stop in the dead of the night. There are lots of restaurant choices as well as contract and Priority Pass lounges, of which DL uses the one in T1 (Skyview?), although it's not available as a DL passenger until 2-3 hours before the flight. In the morning, check out of the transit hotel and retrieve your stored luggage just as DL's check in opens.