This looks like a repetition of what I've already suggested.
Q1. As shown ion the braille examples, OMIT THE CARET. The text identifies the symbol as a directiion to insert a comma, something the braille student will not actually do. Again, refer to that section in Formats mentioned in the earlier post that states that print formattinig symbols are not used in braille.
Q2. That paragraph is NOT displayed. Its margins are 3-1. It is an indented paragraph. It is not displayed because it IS the exercises item. It is not displayed WITHIN the exercise because it IS the exercise. I believe that is what was said in the previous post.
Q3. Headings are not determined by the size of the print or where they are located on the print page. Heading levels are determined by how they are intended to be read. It is true that print size and prominence is a good place to start, but appearance is only an indication. Commas in Sentences Application is not accurate here. Repeated headings generally indicate what follows, or what is under them. I have indicated how the headings are interpreted. You may, of course, disagree. But I have shared how I would do this.
Formatting is open to interpretation of course. I can only offer the consensus of what I would do myself and what most transcribers would do. The additional samples that you sent confirm my original interpretation and there is nothing different that I would say about the formatting.