Hi,
I have some questions. Gracie is 8 months old and our first yorkie.
1. She is skittish and jumpy is this normal?
Totally normal... these poor little guys are so tiny and everything is scary...however if you drop something and she gets scared don't pick her up and coddle her. you are just reinforcing her being scared... just ignore her and carry on.. i know it's hard when they start shaking and want to be picked up
2. She will not come. What is the best way to train her to come?
My mom and i trained Layla "come" in one day.. it take two people... you each need treats 
and just go back and forth... saying "Gracie COME" and then BIG treats when she does.. only tell her once tho... and tell her good girl as she is coming... when you are training come and stay these "tricks" get BIG treats beacuse they can be life saving and you want your dog to listen 100% when you tell her to come or stay... so at first... you will ALWAYS reward COME... then start phasing it out... sometimes she gets treats.. somet imes just praise.. but enver phase the treats out all together or "come" won't work so well!
3. Is it ok to feed her can food of one brand and dry of another? I would like to feed her can food in the morning and dry in the evening but, I am worried she will refuse to eat the dry. She for the most eats dry. I would like to spoil her a little.
that's fine! as long as it is a good quality food.. like Merricks or WEllness or Solid Gold. If she starts deciding she is going to hold out in the evening for the "good stuff" (wet) dont' give in.. when she is hungry enough she'll eat the dry stuff!
We love her to death. We did not realize that she would be so independent. She has such character. She definitely is smart. If she gets out of the car, she will not come if you call her. If she gets out the door at a friends house she will not come if you call her. At our house she is not on a leash when she goes out. I know she can learn to come but we would like to do it correctly.
Thanks for all you help.
Suzan
P.S. If this seems like it jumps around I apologize. I had my one only wisdom tooth pulled yesterday, so I am on some pain meds and my head is a little foggy