I have GALS, and keep mine in a heated tank - sounds like the earwigs were doing some tidying up for you.
Many people don't bother with heat mats for snails, but I like to see them moving about - ok, the warmer they are the more they eat, but the more they eat the bigger and quicker they will grow.
Sorry to hear that yours have not made it, would seriously think about getting a heat mat should you think about getting some more, also the coco blocks are really good for keeping moisture in and easy to store
Warrensark Stud (rats) Southsea
1.0.0. Cockatiel: Nelson Dilbert, 1.0.0 Blue tongue skink: Worcester, 0.0.2. GALS, ,10.20.0. Rats
1.2.0 Corn snakes: Marmite, Bovrilina & Oxo
0.1.0 Hog Island Boa: Bisto, 0.0.1 Bosc monitor: Colman and 1.0.0 husband