For players who have FFXIV on multiple platform types, I know that in order to have complete access to all parts of Heavensward, you need to buy HW for each platform, but I'm still not clear on what happens if you have both ARR and Heavensward on one system, but only ARR on another.

Here's one piece of the answer that I have found:

Quote Originally Posted by Bayohne View Post
Heavensward must be installed on the client to access the areas that will be added in Heavensward. If you are planning to log back in on a client that doesn't have Heavensward installed, make sure to log out in an FFXIV: ARR area.
However this only addresses the regions of the new expansion. What of the expansion's other features? What if, while playing on your Heavensward-enabled platform, you make your character a Dark Knight? Would you then be able to play as such from your other platform? Or what if you change your character to an Au Ra? Would that lock you out of the other platform entirely?

I know the new jobs and race come with the expansion, but is that requirement on whether you can unlock the jobs and create or fantasia to an Au Ra? Or is it on whether you can even log in as a new job or race? Is logging out in an FFXIV: ARR area enough?