3.) I've been learning about and interacting with Madagascar hissing cockroaches in my Bio lab and learned that they come out of a shed with their new exoskeleton white. Apparently it hardens up and develops the usual pigment over a few days or so? Anyway, I guess the slugs being white was my brain's way of saying they were vulnerable or not fully formed or something.
Just so you know, a lot of insects do this. The discoid roaches and crickets I feed to chameleons occasionally will be white. The roach looks super weird to me since it looks so different.