Shenmue's 3 console exclusivity on PS4 looks ever more uncertain today after Ys Net updated its Kickstarter FAQ.
The answer to the question about additional platform versions now reads: "Currently we are planning development only for PC (Windows) and PS4. Other platforms have not been decided yet. If other platform versions were added as rewards, an announcement would be made on the update page."
This suggests that an Xbox One version could be added as a stretch goal reward.