I'd say the vomit you saw was mostly bile. This to ME sounds pretty common and I'd consider it "normal". It sounds like she just had an upset stomach...have you ever been pregnant yourself?
If she's of a healthy age to be having puppies (most ideal- after age 2) and is in good shape otherwise and the vet thinks the puppies are doing well, then I wouldn't worry as best you can.
The "average" whelping period is between 58 and 65 days. Day 63 is most common though.
It's not too uncommon for first time mothers to go a little sooner than this. If you're ever concerned to the point of insanity, I'd go to the vet and have him test for fetal heartbeats. If all is well....just wait, that's all you can do!
I'd probably cut back on the canned food personally, although loads of things could've caused the vomiting. It's just that giving your dog(s) canned food (there are better brands out there now though) is like giving your child Doritos for breakfast and Cake for dinner. There's really not much good for them in it!
Congratulations, keep us posted!
