You can buy an EFB test, you Should pick one up to confirm.
They were gray, twisted. Some melted.I have seen twisted gray larvae that got chilled. If there is any hint of orange tint to the larvae, AND a spotty capped brood pattern, AND a solid egg laying pattern, then I have seen cases where that hive dwindles and requeens repeatedly with worse results each time.
Well it seems you are learning much this Spring. Getting in your hives in an erratic Spring like this is a must. Make up some nucs as a swarm preventive or split.Weather has been historically erratic in the Northeast this spring.
Tough to decide how to manage colonies.