While Amirah is my first yorkie she isn't the first little dog I have been with. A lot of your behaviors that you are describing sound a lot like my aunts dog used to be. He was a mini daschund. My aunt took her dog to a trainer and the first thing the trainer said was that she, my aunt, was not the leader of the pack. He explained that little dogs especially exhibit these types of behaviors when they don't feel secure with a pack leader. There are a lot of good articles online about teaching your dog that you are incharge. I would look into some of that training if I were you I would look up some of these types of articles.
One I found was...
Alpha Dog, Pack Leader, Dog Growling, Dog Bitting, Dog Snapping, Snappy Dog