In my opinion, Both As are correct. Making indirect questions is only confusing when you don’t know what the subject of the sentence is.
Who is a question asked to know the subject or the doer of the action. Therefore, unless there is a pronoun or an auxiliary verb, the noun in the who question is just an object or a noun complement.
Example 1: Who is beautiful? / Who is the best actor in Hollywood. / Who is the king of pop music?
Note: beautiful/ best actor/ king of pop music are not the subject of the sentences; therefore, you don’t need to change the word order when inserting “Do you think”.
It will go like this: “Who (do you think) is beautiful? / Who (do you think) is the best actor in Hollywood? / Who (do you think) is the king of Pop music?”
In the second example, let’s try putting some pronouns and auxiliary verbs…
Example 2: Who are you? / Whom will you send the letter to?
Note: By putting (do you think), we need to change the order of the subject and the verb.
It will be like this: Who (do you think) you are? / Whom (do you think) you will send the letter to?