Yes, they will fall off.
No, they will not recover or start growing again.
New leaves will not grow in the same place to replace the ones that fall off.
New leaves will sprout from higher up the plant.
They should start looking good again in 7-10 days, fear not, young plants will bounce back quite quickly once conditions are better.
Seaweed tonic is excellent to aid in recovery, it can be used in weak dilutions (half strength) every 3 days until growth recovers.
Do not fertilize your plants until they are once again growing strongly, maybe in 2 weeks or so.
Hope this helps, Organoman.