Congrats on your new addition!!! How exciting.
Bailey was 1.8 at 9 weeks - now she is 5.1 lbs - the perfect size for us.
With all the recent changes, I wouldn't change her food for a while.
As far as Bailey - I couldn't get her to eat dry or canned food for the longest time. So, at the advice of my mom, I switched to a raw diet. Bailey just loves it. I know its not for everyone.
A little heads up - the next few months will be filled with love and anxiety. You'll have diet, potty training, and training in general to get through. I'll admit there were a few moments that I wasn't sure I was going to make it - but now, I am so overwhelmed with love - I can't believe there was perfect yorkie just for me and that I found her.
BTW - I like Tia much better than CoCo. Tia sounds small fragile and beautiful.