Pine shavings are good, grass hay of any kind works well too. Don't use newspaper, too slippery, no cedar shavings.. It's best to wait on the treats until they are 6 weeks of age, however a tiny bit of scrambled eggs is healthy for them. Don't leave any egg in the brooder after they are done eating, the heat can make egg go bad.
Not under the tongue though. The tracheal opening is there.
I wouldn't use the corn cob bedding because it looks too much like chick starter. And I most assuredly would get them off the cedar bedding. You might want to also notify the school that they should never be on cedar bedding because the aromatics from it is very hard on their respiratory systems.
I've never used it so I looked it up. Some caution against it that if it gets wet, it holds the water and can become mold. I don't think that'd be an issue if it's not getting wet and/or cleaning often.
