I also like the idea of making the practice test a cold open, and then going to the other stuff after that.
For the scene where Fives and Echo speak to Shaak Ti, I wonder if you could find a clean read of Dee Bradley Baker saying “Echo”. Then, when the camera is on Shaak It’s back, as she is standing there silently, you could have the line “Echo” play, then it cuts to the shot where Fives gives Echo a look, and then Echo says, “General, may we have a word with you?”
So it is like Fives is asking Echo to speak for them both when no one is saying anything. And it would make it clear that it is both Fives and Echo in that scene. Also, the last two or three shots of that scene where they don’t say anything are super awkward. I wonder if you could have the shot where she says, “You are where you need to be” then cut back to Echo and Fives, and transition from there. I don’t know if you left it this way because of an audio issue or just because that’s the way it was originally, but it feels weird!
You might be reluctant to do this, but I think you should cut the “Goodbye 99” scene entirely, and move the desertion scene in its place. Hevy has been hotheaded this entire episode, and after they failed their test, I don’t think it makes sense for Hevy to be so upbeat with 99 as he is leaving.
So they fail, it cuts to 99 overhearing their instructors talking about their failure. The lights in the bunks are dim, implying it is night. 99 hearing about how they failed their test makes him come back later that night to check on Hevy, because he knows how hard he’ll take the loss. In the next scene as the cadets are going to bed, sure enough, Hevy is going AWOL. 99 catches him, though, and argues for him to stay with his team. We don’t see Hevy leave, so we can infer that he didn’t. I think you could use that Kamino dawn establishing shot here (instead of before the final test), and show as the clones are boarding the Star Destroyer. It can fade to black on the final wide shot, and then we could get the TWO WEEKS LATER title card here, then go into Rookies.