It would be interesting to know 1) whether Harry's wand was made after Voldemort's or at the same time and 2) whether Dumbledore DID have something to do with the wands.

As for the loss of the feather, I think that Fawkes signalled Dumbledore that Umbrigde was coming by sending his feather. It seems like that would be a frequent enough thing for Fawkes to do that there wouldn't be just TWO feathers of his in circulation. So... either that's a rare thing and that feather is REALLY significant OR its not rare and that feather is something like the leprechaun's gold. A representation but not a feather freely given. Or maybe the phoenix has to give it knowingly for a wand. *shrug*