Did that question stem happen to be from PT2?
I'm not sure I've seen that particular wording since then.
I think you're absolutely right that that question stem reads as much closer to a necessary assumption than a sufficient one. I also think that question stems that read "the argument above most conforms to which of the following principles", and "which most accurately expresses the principle underlying the above argument" read a bit more like necessary assumptions than sufficient ones.
But the distinction between necessary-ish and sufficient-ish seems to me to be a waste of precious time. There's a danger in over categorizing questions - you can get stuck in minutiae that prevent you from seeing the bigger picture.
With all of those Principle - support style questions, if you simply view them as strengtheners that need to match
the argument, you're focused on the right task. Most answer choices will be conditional: make sure the trigger matches the premise information, the result matches the conclusion information, keep in mind the correct answer could be in contrapositive form, and you're good to go.
Wrong answer choices on Principle-support questions are typically not going to hinge on small distinctions between something that completely validates the argument (but goes slightly too far) and something that we definitively need for the argument to make sense (but doesn't quite perfectly validate it).
I'm afraid I'm not familiar with the term "major premise requisitions" though.
As for Principle (Apply) questions, again, I don't think the categorization of them matters nearly as much as understanding your task. It's an inverted version of the same task you have for Principle-support: now you get the conditional up-front and have to match it to an argument or situation. I think of them as a version of Inference questions, but I perform the same "match the trigger to the premise, match the result to the conclusion, beware of contrapositives" process as before.