Hi there, I'm a product manager working on AMP.
Regarding the Adobe Animate plugin, it's supposed to be in the prerelease channel later this week or next week and launch in a few months.
Regarding GSAP integration in AMP, we'd love that! AMP is an open source project and as long you as the library can be ported to the open source repo as an amp component, we should be good shape.
We are organizing an ad developer workshop in NYC on Mar 20th to get as much developer feedback as possible. If you'd like provide feedback, feel free to reach out to me (jasti@) or the #a4a-discuss channel on the AMP slack channel. (Details above).
Also, if you are an ads developer, you may find https://medium.com/ampfuel/use-amphtml-ads-for-ad-performance-page-usability-user-safety-a36dd70b1100 or https://medium.com/@cramforce/but-what-about-the-ads-bfe5025b6606 more interesting .