Automatic Node Reference my task is, to create a forum-like behaviour which resembles StackExchange's platform with the only difference that only the question's poster will be able to comment on the replies.

My thought is to create a Content Type that describes the initial post/question, and then add a "Reply to this" button that should somehow create a new node of type "Reply" or something (ideally in the front-end, but that's another story - feel free to comment on it though) that should get automatically referenced to the initial post/question.

The "Reply" Content Type should maybe support Drupal's core comment functionality but restricted somehow to the initial post/question's creator.

The basic question is the automatic referencing. Other than that if you got any idea about the front-end content creation and/or the limitation of comments to the afforementioned role and CT, I'd be glad to get some extra input :)

EDIT: using Entity Reference module, not Node Reference module, fyi.
For the automatic referencing you could use entityreference_prepopulate. So your button to answer from the question node would link to something like node/add/answer/27 where 27 is the question node nid. The module supports to hide the field once the value is in the URL so the user dont have to see the field.