It is not as if you gave the dog with malicious intent. You made a mistake. It happens. You know better now and as long as they love Kaya then that is all that matters right? It seems as if her appearance only bothers you and not your cousin. It may be best to come clean about what you learned about getting puppies from a puppy store maybe that is where the residual guilt is coming from.
In the end you sent them a practically potty trained and healthy puppy who they love now, so it all worked out.
