Wouldn't and won't are not interchangeable in your three sentences. The meanings of the sentences are different depending upon which form of the verb is used.
If wouldn't is replaced by won't in the first sentence, we have:
- Here, you won't say, "May I ask you what is your name?"
Won't (a contraction of will not, the present tense of the verb will with the negative adverb) describes the future from the viewpoint of that future; it describes the future as "its own present." Wouldn't (a contraction of would not, the past tense of the verb will with the negative adverb) describes the future as if viewed from a time further ahead of the present than that future; it describes the future as "its own past."
It is always important to remember that even when the verb will is used as a modal or auxiliary verb, it is not merely a neutral word which places the action in the future. Every use of the verb will also partakes of its original meaning of wish for or want. Thus, wouldn't in your first sentence gives it the meaning:
Looking back at your words as if you had already spoken them, you wish you had not said "May I ask you what is your name?"
This expresses a strong preference for not using those words.
Replacing wouldn't with won't gives the sentence this meaning:
Looking at your words as if you are in the future and speaking them, you do not say "May I ask you what is your name?"
This merely states that, in the future, you do not use those words, with no sense of preference.
The meaning of will as to desire, wish is strong when the past tense would is used, and especially when in the negative as in your sentences. The construction You wouldn't +[bare infinitive] or You wouldn't want +[infinitive] is often used in English to suggest, emphatically, a negative desire or preference:
You wouldn't eat dirt!
You wouldn't want to get a speeding ticket!
‘But you wouldn’t want to read a whole book of text speak,’ I said. (Source)
