Filoni is already on record saying that he sees the animated content as just fairy tale recounts, and that live action is “what actually happened.”
Besides, how does your logic explain why Ahsoka’s head tails were longer in Rebels? Or why she’s not wearing her tube-top outfit during the live-action recreations of the battles of Teth and Ryloth?
Filoni made a point to have Ahsoka’s outfit change from gray to white in live action. We now have 2 different outfits for Ahsoka in her show, and the NEW white one matches the end of Rebels, not the old gray one. Why go through that outfit change if it wasn’t in context to how Ahsoka appears at the end of Rebels? Ahsoka also has a spear at the end of Rebels as well. Where did she get this? The differences in Ahsoka’s appearance is too much to just assume it is the same scene we saw at the end of Rebels.
As for how Ahsoka physically looks, of course live action is going to look slightly different when it comes to head tails from a practical effect standpoint. As for the tube-top… Disney probably doesn’t want a child in that outfit running around in live action.