I've found this helper tool for making Defold animations:
https://forum.defold.com/t/panthera-animation-software-for-defold/71276/8probably it would be relatively easy to modify the code so that it can also export code for Gideros movieclip-based animation (or even better/easier to maintain: a plugin/class to process the json file that it exports to). I thought i will mention it, perhaps somebody is interested in doing it/using it.