I've seen recent pics of Julian and, personally, I don't think he looks much like John anymore. In fact, I really never thought the resemblance was that canny. John had a more expressive-like face. Julian has more plain features...no offense. I mean, he's cute if that is your thing, but his nose is Cynthia's old nose, he has a somewhat notable turkey neck, and he appears to have no eyelashes...the only things I can say he resembles John in slightly are the narrowness of the eyes, his hair color, and the body.
Now Sean looks like his daddy. Yeah, Yoko is certainly there. But Sean has that John-like face and those features that just jump out at you. He's totally a Eurasian John. And as they say, "That's hot."