Is it normal even when you have stuffy ears, to hear your stomach growl?

Yes. You hear by vibrating the tympanic membrane. So while you may not hear external sounds as well when congested you will actually hear internal noises better. These sounds are the vibrations that travel thought your body to the hearing bones. .
Yes. Bowel sounds are normal and are frequently loud enough to be heard even with stuffy ears. They vary by time of day and by what you eat, and may be more frequent before bowel movements. Other than occasionally being funny or occurring in embarrassing settings, they are of no concern. Good luck.