Awww, congratulations on your new baby. Sounds like she is in a very good home with a very loving mommy.
You can check out the diet forum and read up on food. There is a wide variety of opinions on food here. I am lucky that I finally found something that my 2 will eat consistently. I feel Natural Balance Food Rolls. It comes in a big long roll and you can either shave it down or cut it up-which is what I do. My babies are 4 1/2 and 5 lbs, they get a 1/4 cup each in the morning and evening. I also have to bribe them at times so I wil put some shredded turkey, cheese or something to get them to start eating. lol Once they start, they usually will eat.
As for treats, I like to give them veggies, some par boil in the nuke just to soften them a little. Please learn what can be toxic for your dog. I was very surprised. Onions, raisins, grapes, mushrooms, apple seeds and avocado are big no no's. Since your are using pureed baby food, just make sure there is no onion powder in it.
You can also try adding some boiled egg and mushing it up in her food, maybe that will entice her as well. or mashed up sweet potato, carrots, green beans, peas. Plain yogurt is good too, it will help her tummy as well.
As for vitamins and supplements, my suggestion (and others will probably know a bit more) I would take your baby to a good vet who knows about little dogs, and take with them about that. There is so much that is out there, it is best, in my opinion, to start with a good base knowledge that the vet can give you.
Good luck and welcome to YT.
would love to see pictures of your little Kiley.