Normally? Zero. LGA has a curfew from midnight to six AM, April 5-December 31.

In practice? It depends. Delays have a tendency to cascade in the air travel system and the Port Authority can curtail or cancel the curfew at their discretion. How frequently do exceptions to normal ops have to happen for it to be unreasonable to use "normal ops traffic" as a justification for scheduling a single controller? Ultimately, controllers have to control the traffic that they get, not the traffic that they want/expect to get, and a system that is overly optimized becomes brittle and unable to deal with exceptions to the norm.