I'm testing the iBooks publication route. I can successfully publish an animation to iBooks widget format which will install and run as a Mac widget. It will also import to iBooks Author and show on the page in preview on the iPad. However when it is tapped to open it, the widget rectangle expands and immediately disappears.
To reproduce, take any of the final state lesson animations (e.g. Reuse lesson), publish to iBooks widget, import as html Widget in iBooks Author, and preview on the iPad. This is apparently successful, but the widget immediately blanks out on open.
OK - some progress...
The problem appears to reside with iBooks Author preview since we have the same problem when previewing a Hype widget.
If you publish to a .iBook file and manually copy it into ipad books with iTunes, then the blanking problem disappears.
Animations that self-play seem ok (like the Reuse lesson).