News for XE-1 and even X-Pro1 shooters...

The Zeiss 50mm is supposed to be f2.8 not f2.0. It's not faster since it's supposed to be a Zeiss macro lens and not a portrait lens. I wouldn't worry too much about it. The X systems should be decently covered with the 60mm f2.4 and 56mm f1.4 for portraits.

The Nikon G lenses are naturally at their smallest aperture if you mount them on other non-native cameras. In order to use them on the Fuji X mount cameras, you will have to buy a an adapter that allows you to adjust the aperture mechanically (there's a little lever on the back of the Nikon G lenses that allow you open and close the aperture). I currently use one to use my Nikon G lenses on my Sony Nex 5N. However, you have to guess which aperture you are using.