So, thinking about that:

If we want to have only one test, then it should be the first half of the first cut into the second half of the second. The first half of the first because it has the main character exposition.
If we have the first half of the first, we therefore have the combined test overseen by Shaak Ti rather than by Commander Colt, because she gives the exposition.
Commander Colt is necessary to show up to tell them they’ve failed, but I don’t think it’s particularly worth emphasising his character via the introduction/Bravo squad scene, EXCEPT if the replacement start needs a slightly punchier kick-off, which his scene gives. (Without context, he’s just an instructor or adjudicator.)
The Bravo squad scene would only slow us down, I think it’s only necessary if this episode itself has a three-act structure, which it no longer does.
Scenes that should definitely be kept if we’re going for a single test version are the second test, Bric and El-Les’ recut dialogue which emphasises failiure, and Hevy deserting.
But before that second test, we currently have the clones arguing about failing their first test (quite useful but not a great opening), Echo and Fives asking to change teams (useful and good but not a great opening), and Shaak Ti and Lama Su discussing clones (not vital and distracts a little from the main message of this act, but fine).
None of those really work as an opening scene, and I don’t think the Commander Colt scene would fit there since he’s implying they’re going to be tested right away, but cut this way they’d go to bed and stuff.
You could maybe start halfway into the clones arguing with themselves scene, at the part where Bric calls them down from bed and tells them they’re useless. That, I think, is the only decent start other than the first, if it follows from an intro which explains they’ve failed their final practice test.
Therefore I think the only viable alternative would be: Bric criticises Domino Squad for failing > Echo and Fives ask to change teams > Combination first/second test FAILED > Bric and El-Les confirm fail > Hevy attempts to desert > TWO WEEKS LATER into Rookies.