Hi! My name is***** and I am a small animal veterinarian and I have extensive experience training dogs.
Your question about Quincey is a very good question to address, interestingly growling, and attempting to bite when touched during sleep or rest is not uncommon especially in working dogs breeds like the Catahula.
When Quincey growls and shows his teeth when he is disturbed he is giving whoever is touching him a warning not to bother him. Often biting occurs when this warning is not heeded and the touching continues or when dogs are surprised by an unexpected touch.
I realize that this behavior is not desirable but this is one time where old sayings come in handy...it really is best to let sleeping dogs lie.
Ultimately my suggestion is to not to allow any one to bother Quincey when he is sleeping. This can be tough if you have other pets, children or visitors. If pets children or visitors have already had problems it is best to supervise all interactions at all times or even confine Quincey to an area of the house when he is most likely to sleep where the children or pets cannot have access to him to bother him.
The safest way to deal with Quincey if you do need to rouse him from sleep is by waking him up at a distance using and excited voice and saying "come" then rewarding with treats when he does will usually help teach him to respond quickly.
If you try these steps and the problem continues it is a good idea to discuss the problem with your local vet just to make sure they do not think that there is an underlying health issue.
Another step you could take to promote calm behavior and maybe make Quincey a little less grumpy is to use Adaptil, it is a calming pheremone for dogs and can be purchased on Amazon. I don't expect this will "fix" the behavior so I still do not recommend allowing any person or pet to bother Quincey when he is sleeping.
Please let me know if you have any further questions, I wish you and Quincey the best of luck.