"the most logical assumption would be that it will be a port released after its initial Xbox launch"
Those days should be over. There's not much logic or worthwhile strategy in a delayed port at this point, it's just dead money and missing out on the hype cycle.
Only small outfits who have to prioritise resource allocation should be delaying ports. At this point all MS's own releases should be day at date just like any other 3rd party publisher.