I wish you and your DD well greenlotus. You have had excellent clarification and advice. Think of testing as an information gathering task. Information is useful for you to make decisions as much as it is for the school.
We chose a small high school, no middle school here and high starts in yr 7, for exactly the same reason you did, we didn't want DD to be lost in the crowd. It is good as it worked from that perspective. The downside is that there are fewer teachers and fewer class streams. It is harder to juggle a timetable when she is subject accelerated as different years can't have the same subject at the same time! However, she has peers across all age groups which is helpful now she is full grade accelerating. All choices have upsides and downsides but our DD consistently exceeds our expectations and yours will too. And I don't think it is because we set the level of expectation too low, kids are just full of so much more than we can clearly see.
There are so many kids who have issues with organisation. Our DD improved when she went to High School because it was meaningful to her to be more organised, because she had to be and because she had friends around her who modelled more organised behaviour. Her best friend would regularly reorganise her locker with her and the GT/special Ed teacher gave her an organiser for her locker. Now she talks about helping other kids with their lockers.
All these skills can be learned to different extents, some kids take longer but seeing how other kids do it was a big help for us. These are skills, locker organisation, moving between classes, remembering to have books and materials etc, that couldn't be modelled for her until she was actually in the environment using them and watching other kids managing.
Take a deep breath. Tell your DD to show what she knows and the test will work out what that is, nothing more. Once you have the results, go from there. Best wishes.