Looking into this a bit more - it seems that back in the version I was using (2.3.1) the selectedObject setter was calling the highlight function, which called OnHover on the selected button. This no longer happens. Was that an oversight?
What i want is pretty simple: A highlight sprite that has a looping tween that's activated when the mouse hovers over that button, or when it's selected with a controller. When the mouse leaves the button or the selection changes to another button, I want the highlight to go away.
At the moment it seems like I need to use 4 tween components on a button to accomplish this properly.