I think if you are willing to rebuild the front hub yourself, go ahead with the carbon wheels. The Novatec or Bitex hubs are good, not the level of a DT Swiss or SRAM XX hub, but more than decent. I've not read any posts about people complaining the hubs are crap. For the Lefty fork you will need the new front hub, spokes, and probably new nipples but totally doable.
I went with the 30mm wide rims but depending on your weight and terrain, you could go for the more narrow rims.