I have normal greys, whiteface, pearl pieds, creamface cinnamons, and pearls.
Well first of all that isn't much of a vet if they don't know how to get a simple drop of blood for a DNA test! you can really do it yourself. All you need to do is clip a toenail short enough to draw a SMALL drop of blood for the test you can send off to get. It costs a whopping 14 bucks and you get results in about a week and a half. I'm like Luka, really need a underside view of the tail but since you say your bird is LIFTING it's tail and squeaking, that sounds like a female wanting to mate!