You are very welcome.
(you will get some great advice from others on this subject who are professional trainers etc., which I am not)

The reason for the hand feeding, is
just to strenghten your Alpha roll with
her, even though she doesn't care about
her regular food only special treats.
IN my house it's the meaty bones from the butcher that my dogs will kill over.
My senior alpha female Akita who will let me do anything to her, but when it comes to those special grocery butcher meaty bones She has made a low growl, when I have gotten my face right next to hers. (I do not suggest you do that)
Her growling at me is not acceptable, and I will repremand her and make her give me that bone. With her, I must periodically re-enforce that behavior training.
In your case it is the meaty/treats.
I think you are very wise not to give anything to Brinna such as meaty/treats
around your little boy. No matter how well trained your dog is, In my humble
opinion you can never "100%" fully trust any dog around small children un-supervised etc.
Dog are animals, have their own instincts and behavors, and have a pecking order.

Brinna sounds like a wonderful dog.