Well, now I'm confused. Mounted the Mondonico FiR wheel on the Felt and no noise. The wheel was out of true again, after only 15 miles of riding. So this seems like it should be the source of the noise. The only other thing we changed was clean and added grease to the skewer... it possible the the skewer is causing any noises?

Next step, I will put the FiR wheel back on the Mondonico and take a ride to see if the noise reappears. If no, problem solved (oddly). If yes, then mount the FiR wheel on the Felt again to see if it will be noisy.