Why would the 737 "see very slightly different winds," regardless of whether two passengers are aboard, or not? The weight of the two passengers is less than the tolerance in the fuel system indication and the APU fuel burn, and becomes entirely inconsequential with respect to length of taxi or any other delays; the airplane may well burn more fuel than their weight; or may burn less. If the 1,000 lbs of fuel burn is assumed for takeoff and the aircraft burns 500, then it's already made up the difference in weight of passengers.
Because the takeoff numbers are spelled out in values that won't reflect a difference with the weight of the two passenger(s), their presence is inconsequential. Two passengers will not require a different flight level.
There's a lot one can do to end one's life early, but when it's your time, you're done.
Perhaps a more useful question might be what would have occurred had the occupants of the 152 elected to take a train to JFK and hop that 737 back to Miami.
Then the collision would have occurred between the 737 and some doctor in his Bonanza. It would still happen to the two occupants of the 152, and everyone on board the 737. Plus one of the two who missed their flight at JFK. He'd be crushed in a tragic escalator mishap on the way back out to the parking lot, and the other one would slip and fall in the restroom, striking his head on a soap dispenser. Karma is an ungrateful sod, and one determined *****.