yellow is good.
my dog always barfs yellow.... so i'm guessing thats a good thing.
make sure he drinks lots.
when's the last time he took a shit? or peed?
its probably the bone for sure thats got him barfing. especially if he's not used to eating those things. the first time i gave my dog mcdonalds fries, he barfed about 4 times in a row. but im guessing it was the salt. or maybe the fact that he never ate that kind of stuff before and his tummy didnt like it. i dunno.
if you're really concerned, call your vet, they should give you symtoms to watch for and tell you what to do.