What does "Original Language" mean in cases of ambiguity?

Hello there. I'm a new contributor trying to fill out the credits for Rabbit Academy: The Series, including some that aren't there right now. The Cast section is currently entirely empty. When adding voices, there's a warning: "Please only add voice cast from the original language version of the title."

Rabbit Academy: The Series is produced by a German company, based on a natively German-language franchise, and the only version that has been released as of now is one with a German voice-over; we don't even have the names of the English cast, or any concrete indication that the series will be released in any non-German language. However, the writing team seems to be largely English-speaking, they post about the series in English, a storyboard reel that contains footage of the series demonstrates that it was boarded to an English scratch track, the lip-syncing of even the finished version appears to not correlate perfectly with the German audio (my theory: because the lip sync is to some unseen English version), and a version of the theme song/opening credits in English is available, listed as the international version. This version is the version the writer mentioned earlier shared.

With this information, should the German voice cast be listed as the voice cast and any future English cast under dubbing, or should the German voice cast be listed as the dubbing cast and the main cast left blank for the international/English release?

I have looked through rule documentation but perhaps not thoroughly enough to find a concrete answer, if there is one.

Thank you,

Nev E.