Q: What is the correct and more-native position of the word 'are' in the following sentences? What is the correct and more-native  position of the word 'are' in the following sentences?
*someone asked me what are my plans for halloween
*someone asked me what my plans for halloween are

A: We either say

Someone asked me what my plans for Halloween are.

or

Someone asked me what my plans are for Halloween.

But we never use your first sentence. That word order is for asking a question,

Someone asked me, "What are your plans for Halloween?" 


A: 
[1] * Someone asked me [what are my plans for Halloween].
[2] Someone asked me [what my plans for Halloween are].

The position of "are" has an important effect on the grammaticality.
The bracketed elements are subordinate interrogative clauses (embedded question). Such clauses do not normally have subject-auxiliary inversion, and hence [2] is fine but [1], which does have inversion, is ungrammatical. 
The meaning of [2] can be glossed as "Someone asked me the answer to the question 'What are my plans for Halloween?'" 
