Keep in mind that toxicity is not the only thing you need to be concerned about. Fatty foods can be a contributing factor to pancreatitis, which can smolder for a long time and then blow up. After an attack, dogs are usually at high risk for the remainder of their lives and must have their diets carefully monitored. Salt content is another concern.
Also, long-term, weight may become a issue. Unnecessary weight is hard on Yorkie knees and other joints, and it is hard on their vital organs.
Keep the treats very small and limited. Love that little face by doing what is right with her diet.