It is not necessary, however the chilling pack must be flat and free from bumps to fit in the rubber base properly. It’s recommended to freeze completely flat for best function.

The medium, 3.5L bowl holds approximately 15 cups

Yes. It is designed with locking snaps to hold securely and tightly. Since the main lid does not open often, the access lid will be used more and requires the main lid to be tight for functionality.

No, the access lid, should remain on. It is not designed to be taken off regularly.

Although it is not recommended, it would be safe for the microwave.