19 minutes ago, Nytwyng said:At Celebration Orlando, I believe Filoni said that it’s Rex as far as he’s concerned, but you’re also right that it hasn’t been “officially” (whatever that means) been adopted into canon.
I think officially, in this case, means that it actually is shown on screen that the two characters are the same. Creators talk about things that don't pan out all the time, after all, and Filoni is surely aware of that.