I have never "stuffed" chicken with greek yogurt, but I'm sure it would be great- though it might leak out/melt all over the place. I have marinated chicken in yogurt before, frequently, for Indian food recipes and it keeps it moist and delish! All of the ideas you came up with sound great! I also like stuffing chicken with light laughing cow wedges mixed with herbs, lean ham lunch meat slices, and asparagus stalks- it looks pretty, too.
Pretty much stuffed anything is delicious- so you should do it!