[chryuop]

I was watching on youtube the "human being" version of an old anime in Japanese (with English subtitles or I would have understood nada lol).
Let me say in advance that the relationship between the characters is kinda weird. They are on a polite form of conversation, but since they fall in love they also drop sometimes in a more confidential way of talking. So the next couple of questions are due to the fact that I am not sure when they use them.

あの Is this form of attracting attention (like "excuse me" or "listen") confidential or is it used also in a more formal situation?
どうも I have heard many times in that show using this expression to say "hello". I assume it is a friendly way to say it? (it confuses me coz the same people alternate it. Some mornings they say どうも and some days おはようございます).
どこの this one comes from a book I am reading, but it is not the first time I meet this use of it. In the book I am reading someone says that he needs to go to work and the other person replys どこの会社？and then goes on 俺は会社名をいった so it clearly means what is the name of the company. In another book I remember clearly this expression to be used to ask for the name of a person. But doesn't どこの asks about a location and not a name?

お願いします.