I'm really sorry that I never responded to this! I did not see it and did not get notified of a post. I'm sure you've moved on past this but I'll still say that I think I would do it as a list and repeat headings as necessary.
Centered table heading
Vector Orientation at the margin
Vectors are Parallel in cell 3
Calculational Strategy... in cell 1
Add or subtract... in cell 3
Vector Orientation (repeated) in cell 1
Vectors are perpendicular in cell 3 with the diagram following
Calculational Strategy ... repeated in cell 1
Use ... in cell 3
Use (new paragraph) ... in cell 3
You could combine the headings "Adding two vectors" and "Limited usefulness" into one heading.
You would for sure need a TN to explain that you are using a list format for the table and that headings are repeated as necessary.
This is, for sure, super complicated!