It is normal for any breed of dog, however gentle, to protect something they are eating. A bone this big probably seems to her like the biggest bone in the world, something like you being given a $20,000 diamond necklace. How would you feel if someone were about to take that necklace away from you? An 8 week old puppy is a baby, and babies have no manners. Her behavior is normal and instinctual. In order to get her not to defend food she will need training. Puppy kindergarten class is a wonderful way to teach them manners and how to behave in a lot of different situations. At the same time, you will have to watch that your son does not bother her while she is eating, at least until she is very well trained and reliable in that department. GSDs are highly intelligent and motivated to please, so training her should go smoothly. A lot of trouble can be averted simply by managing the situation. Set her up to succeed rather than fail. Give her the bone while she is resting in her crate, not right beside where your son is standing. Instruct him not to go near her when she's eating, and be prepared to enforce that repeatedly until he gets it. If she does bite him again, give her a stern scruff shake and a gutteral growly, "AHHHHHH!" Biting children is not allowed, ever. When your son is older and more coordinated he can start putting her food bowl down for her and you give her the release command to go ahead and eat. This will elevate his social status in her eyes. Most dogs see children as subordinates or as littermates. I'd say you have a very workable situation here - you just have two impulsive babies who need to be taught manners. They can grow up the best of friends with proper management. BTW, I'm glad to see that you understood her peeing for what it was - excitement, not a housebreaking issue. Submissive urination when excited is very normal for puppies, and almost all of them outgrow it. It's best to just ignore it and not make an issue of it, since correcting her will make her want to submit even more. If it's an issue, greet her outside on the grass where it won't matter if she pees. Once the initial excitement of greeting is over, you can bring her back in with you. Congratulations on your new family member. I hope you enjoy each other for a very long time.