Interesting meme. Though I tend to think of Harry as being a quadruplet - his brothers are Snape, Tom and Hagrid. I'd tend to twin Vernon with Lucius, because one of my favourite ironies of the series is that the Malfoys seem to double the Dursleys. Dumbledore is an only child - Voldemort is too far from being his equal to be able to count as his twin, I think. None of the bigwigs in the Ministry can come close to matching him either.

And apart from that, I absolutely agree with you!