I worry that some people will never read the Techniques or rationale and thus the checkpoints need to stand on their own in a checklist. Perhaps shorten the paragraph from the rationale and move it to a Note of checkpoint 5.2. The current note only talks about assistive technologies, not recognizing access flags. The first bullet discusses sequential access and gives the example of tabbing through links. However, one of the complaints of tabbing through links is that link context is lost.
Structure seems to refer to headers, paragraphs, etc. rather than among the cells of a table.
While 7.4 seems to be a special case of 7.8. Therefore, in general these seem to overlap quite a lot and are perhaps not general enough. I do not see a clear proposal for how to make them less overlapping or more clear. Granted, it's a p3, but it might send a weird message. For example, in the visual browser, a pop-up appears.