My Chloe is the QUEEN of fussy eaters. She wouldnt eat any dog food and I had tired dozens. I always heard if they are hungry enough they will eat. Not her, she actually got the shakes from not eating, I promptly gave her honey and anything that she wanted at that point lol. The only "dog food" she will eat is raw food which I have had her on for almost a year with awesome success. She is super healthy and happy, it may be an option for you if your little one is as you say skinny and fussy as that sounds like "princess Chloe". If your interested in trying a raw diet you can see if any of the smaller pet food stores in your area carry it as I have never seen it offered in any of the larger chain stores. I purchase Chloes food at a small independant pet store.
Good Luck!