[mom of 3 dogs]

just checked to see what i have.. and measured them also. the neck would not be too big like you described in the xs walmart dresses.
the length on some will be perfect and some may be up to an inch too long.. and the girth will be roomy but i dont think will look too big. they mostly all measure around 11 inches but i think for a yorkie having all that hair, its nice for them not to fit roomy.
i would not recommend the XXS in ruff ruff. i think it will be too snug

just curious , how old is your girl?

here are the ones i have here. sorbet hoodie, shopping dress, scarlett dress, butterfly dress, little piggy dress, cotton candy dress, sally dress, hampton dress and first pooch top

i do have some others i didnt advertise here. they are by the make little lily. they are stored away so will take me awhile to see what i have. this make runs smaller than the ruff ruff couture.