The Zeppelin action, from the SteamPunk faction, has a talent to move a minion to or from the base on which it was played. It does not specify "ongoing" in its text, but it seems that this has to be implied with the talent, otherwise it seems entirely useless. Is there any guidance on this?
No, it's not ongoing. Moving, like destruction, is a one-shot effect (to borrow Magic: The Gathering terminology). The move happens when the talent is used, and that's it.
If it was ongoing, the move would stop when the Zeppelin leaves play. How do you stop something that's already happened? That makes no sense.