Neither of the 1. and 2. forms are strictly academic. The "vous" construction is slightly less correct than the "tu" one, which at least has a leading "Comment".

Based on the very same words, many combinations are possible. All of them can be commonly heard and will be understood. Here they are from colloquial to formal :

– Tu t’appelles comment ?

– Vous vous appelez comment ?

– Comment tu t’appelles ? *

– Comment vous vous appelez ?

– Comment t’appelles-tu ? **

– Comment vous appelez-vous ? **

* This is the most frequently used.

** These are the ones taught at school.

“Comment tu t’appelles ?”, along with “Comment vous vous appelez ?” are technically and grammatically incorrect, although they are commonly used in current, spoken French (something that was mentioned in the answer on the post you cited yourself).

“Comment” is perfectly acceptable at the beginning of a question if the question is formed with inversion:

Comment t’appelles-tu ? / Comment vous appelez-vous ?

or with the use of “est-ce que”:

Comment est-ce que tu t’appelles ? / Comment est-ce que vous vous appelez ?

There are two differences between the proposed constructions:

Using tu or vous

I suppose this is not the problem and won’t even stop on this. If this is a problem, I suppose a separate question would be better.

Order of the words

As Casey said, both proposed structures are used but both fall outside of the grammar rule book we learned as children. Below is a summary of all constructions I know for this question.

Please note these constructions can be applied to any question, hence another totally unrelated example for each.

Informal, almost only oral

Affimative proposition + interrogative pronoun/adverb + “_ ?_”

• Tu t’appelles comment ? / Vous vous appelez comment ?
• Tu es qui ? / Vous êtes qui ?

Informal, common at oral

Interrogative pronoun/adverb + affimative proposition + “_ ?_”

• Comment tu t’appelles ? / Comment vous vous appelez ?
• Qui tu es ? / Qui vous êtes ?

Common

Interrogative pronoun/adverb + “est-ce que” + affimative proposition + “_ ?_”

• Comment est-ce que tu t’appelles ? / Comment est-ce que vous vous appelez ?
• Qui est-ce que tu es ? / Qui est-ce que vous êtes ?

Formal¹

Interrogative pronoun/adverb + interrogative proposition (subject inversion) + “_ ?_”

• Comment t’appelles-tu ? / Comment vous appelez-vous ?
• Qui es-tu ? / Qui êtes-vous ?

_{1. Though more formal, this may seem more natural to a native than the “common” construction depending on the question. “Qui est-ce que tu es ?” for instance, though grammatically correct, is almost never used, while “Qui es-tu ?” is standard. Natives will understand any of the above constructions nonetheless.}

_{Thanks for noting this answer is largely based on Casey’s and jlliagre’s answer because I think this view is interesting.}