Just my 2 cents but I'm not impressed with the limited ingredient foods I have seen online. I only glanced but synthetic vitamins are not the best and many times not metabolized well by the body. If you do decide to try home cooking there is a supplement made of mostly real food vitamins that contains some of the enzymes that kibble looses from cooking.(or home cooking) I have been giving it to Gracie with great results from the time she was a puppy. I home cooked for her for quite a while and wanted to make sure she was getting as much nutrition as she should. It's called The Missing Link and comes in a couple of versions but the Skin and Coat is the original. It is great for the coat but has all the other necessary nutrients. It is in powder form. It does need to be kept refrigerated after opening.
The Missing Link Ultimate Skin & Coat Supplement For Dogs at PETCO
This can also be added to kibble or any other type of diet.
If you did home cook for her you could try feeding her in another room so the others are not jealous or feel like they are missing out on something. I know that is quite a thing to pull off with Yorkies.
Gracie did not care much for the food I made her until I switched from rice or oatmeal to sweet potato instead of the grains. She just fell in love with chicken and sweet potato along with other veggies.