Hi Tom,
Seems like there are two question and our development team came up with the following answers.
>Is it possible to invoke OOTB liveactions, such as contentUpdate, from a custom liveaction?
>> No, We do not support this.
>Can we trigger the creation of livecopies based on event like “tagging” and “language
creation” ( assuming that tagging/translation happening on master)
>> No, we do not any process to create live copies based on these events.
It might be possible that you have missed information to provide which could give more clarity to your queries so Please let us know if you have more info on that which clears the requirements.
Thanks.