The names for Grimoire of Gaia mobs in your AbilitySupport.json file need to be changed for them to have abilities for Morph. The mobs have been moved from "gaia.entity" to "gaia.entity.passive" and "gaia.entity.monster" (Although, I think all of the ones you're referencing for abilities are under the monster category).
I wasn't sure if you'd prefer me to leave this info here, make an issue on the FerretShinies github page, or (learn github and) make a pull request. But seeing as there aren't any other issues or pull requests, I figured I'd try here first.
The mobs are already updated in
iChun's version of the file, so it should be easy to copy and paste the changes unless you've customized their abilities. Although I did notice he has two more mobs listed, Kobold and Hunter.
I should note that online players should notice abilities working as soon as it's changed in the online location. The only reason to push a local file update is for offline players to have it work as well. Unfortunately, online players can't just change local files to make it work due to the way Morph handles abilities.