Who is listed on the questions list is dependent on the view you are looking at.
All of the tabs except Active will list the question author.
Only Active lists anything else, and this is because the most recent actor is the most relevant piece of information to that particular view. The Active view lists posts in accordance to the most recent form of activity on the post. This means the initial asking, any answers, and any edits to either the question or the answers by anyone. The signature line will tell you who the source of the action was - this can let you see if, for example, one particular user has gone and made 10 edits in a row, or that someone just answered 15 questions. It essentially is responsible for telling you who is responsible for the post being visible to you right now. That's also why the timestamp is that of the latest action - it tells you immediately what is going on. The original author is not very relevant on this particular sort order, in the traditional utility of that view.
The front page uses the same sorting algorithm as the Active view, so consequently it uses the same logic to determine whose name is shown. This actually has a secondary effect as well. On the front page, the time stamp next to the username will link to the post where that user performed an action. So if it was an answer, it'll link to that answer. If it was an edit, it will link to the post that was edited.
If your interest is in seeing the latest questions, especially if to see if something has come from a particular user or not, I would recommend browsing in the Newest tab. This will not only highlight the author of the question, but also let you browse new questions without the hindrance of bumps, if question activity is not of your interest.
On the topic of listing both - I'm not entirely fond of it because it only affects one view. The "most recent actor" is not all that relevant when browsing any of the other tabs, so you wouldn't need to list both in all those scenarios. You also may consider when the most recent actor is the question author - it gets a bit redundant for any new question as it'd list the same user with the same time stamp twice in a row. Displaying the extraneous information would probably get noisy pretty quickly, and only showing the two sets of users on the Active tab would make a very strange inconsistency in the general site layout.
