Have you tried leaving the food out? I don't think it's a good idea to give him too many different things to eat right now. It might cause tummy issues. Have you talked to the breeder, what does she have to say? Sometimes the new pups can go off food, you have to make sure he eats so he won't have a hypoglycemic attack. Do you have nutrical? Sometimes they'll eat after you give them this. If their sugar is too low, they will not eat. Has he been to the vet?
You keep mentioning petland, if that's the same place that sells puppies, please DO NOT support them. The pups all come from puppy mills!
I have to sit right next to Mimi to eat. She will not eat if I don't sit next to her. She was a very picky eater as a puppy & I had to put 'toppings' on her kibble & she rarely ate it more than 2 x's in a row. I had to switch it & get creative! Foods that are easily digestible like egg whites, scrambled or hard boiled (no salt, no yolk). Sweet potatoes, steamed or boiled. Plain boiled chicken breast, frozen green beans (thawed & diced). Those are her favs. I avoid dairy as it can cause pancreatitis. I've read that dogs cannot digest dairy & it just builds up & they get sick. Absolutely no table scraps!
If you want to switch food, I've read on here that Fromm has a very small kibble. Not sure which formula tho. Please switch gradually & very slowly (14 days), but he's not eating his current kibble...
just switch cold turkey?
Yorkies are notorious for being very difficult to potty train. You must limit his space, not have the run of the house, or he will go anywhere! He's a puppy, just like a baby, can't hold it. Ex pen is great, you can make a doggie apt w/bed, water & food bowl & potty area. Can you line the play pen you have now w/cardboard or something so he can't escape?