Memorize? No. Just know the reason:
Emphatic-do
- To add emphasis to an entire sentence: "He does like spinach. He really does!"
- To add emphasis to an imperative: "Do come in." (actually softens the command)
- To add emphasis to a frequency adverb: "He never did understand his father." "She always does manage to hurt her mother's feelings."
- To contradict a negative statement: "You didn't do your homework, did you?" "Oh, but I did finish it."
- To ask a clarifying question about a previous negative statement: "Ridwell didn't take the tools." "Then who did take the tools?"
- To indicate a strong concession: "Although the Clintons denied any wrong-doing, they did return some of the gifts."
Source
Your examples are irrelevant to and diverting from the topic under discussion:
the order, content and structure (of words)
in a question!
That is, that a normal content, structure and order of words in a question
(taught by learners of English)
may happen to be emphatic.
Does a (normal) question always require auxiliary and if not then when?
Teachers (and students) of English, known to me, do not even know
that English question may be correct without an auxiliary (verb)!
For a learner of English it is not trivial that a normal structure and content of a question (using auxiliary verb) happens to be emphatic.