Originally Posted by
themicah
To be clear, LGA has four terminals, one of which has four concourses. Both terminals and concourses are lettered A-D, which is confusing ... If you're all arriving at Terminal B, just at different concourses, it's all one building and the baggage claims are in the same area. If you are in fact arriving at Terminal D, it's a different building, but still walkable from Terminal B. Services will probably be minimal at that hour.
If OP can post their incoming airlines info, it would be easier to sort things out - anyway, posting link to the "bigger" LGA picture of the terminals, concourses & gates info for her/his easy reference.
For family members arriving around 10 PM, the free shuttle buses will definitely be running to take them over to the other terminal to meet up together. The concourses within the Central Terminal/Terminal B are definitely walkable but for late night, it's a long 15 minutes walk with luggage to the Delta Terminal or Terminal D from Central or B.
The Q48 (yes, the M60) plus the Q33 buses to to Jackson Heights - all of them make stops at all the terminals with less frequent late night services if they plan to use it to get to their hotel - and, they can just as easily call for a car service pickup at any of the terminal as there will be fewer yellow taxi waiting/hanging out around midnight. Concession services for food or snacks will definitely be limited, if open at all, after 10 PM in any of the terminals or concourses - odds are better for someone to stay open in CT/Terminal B.