I think it's very unlikely you'll get motion sick in AR, _especially_ AR with a small FOV. The vast majority of your vision will still be filled with reality, so it won't be all that different from wearing a pair of regular glasses, at least from your brain's perspective.

Not to mention that Magic Leap's multiple depth-of-field display will likely simulate normal vision much better than current-generation VR displays, and that there's no artificial locomotion in AR.