We have been discussing this as a committee, and we have come to some consensus.

First, Let’s be careful to focus on transcription and not instruction/teaching.
If we look at this as a transcription issue, then the conventional wisdom is “follow print.”
To answer the specific questions:

1) BANA does not necessarily recommend transcribing the equation without the “shown work” before transcribing the fully worked-out problem. With that being said, we as a committee do not see a problem including the equation first in this situation. We should certainly use a transcriber’s note if we present the problem twice; perhaps, “The example problem is shown twice: first without any calculation text and a second time with the calculation text included.”
The suggested transcription that is attached here does give the example problem twice with a tn explaining that the problem is shown twice. The suggested transcription uses one continuous numeric passage for all of the example problem and also the rest of the exercise set. The alignment of the suggested transcription attempts to follow the mathematical logic of the problem’s layout without rearranging or breaking down the print layout.

2 & 3) These questions seem to be focused on teaching a braille reader how to show their work, and that is not really the role of a transcriber. We must trust the teacher (or aid or paraprofessional or someone else directly in the instructional environment) to tailor instruction on how to show work to the specific braille user.

Are there aspects of your question that we did not address? How else can we help?