The last two questions have been 1. Te mész vissza vagy kati ? and 2. Te is visszafutsz? They are both questions but in the first question the preverb comes after the verb and in the second question the preverb comes before the verb. Is it something to do with focus and topic. Any help would be appreciated.
Yes, it is about focus and emphasis. In your first sentence, the focus is on "Te" and "Kati". The subjects. As such, being in focus, they are placed right in front of the verb root. Even the preverb gets cut off the front of the verb. ("Kati" is in front of an omitted verb, you can imagine it there).
In this current sentence, the main focus is on the verb itself. The question is mainly about the action. And when the verb is in focus, it stays intact.
Good luck with that! I never noticed such things myself, at least not consciously, until I started explaining these things. :)
But it seems like a good rule, which stood the test of times: when the verb is intact with its preverb, it is definitely in focus.
Sometimes it is very useful to create a question pair for these sentences (when they are not questions themselves). That helps point out the focus.
"Yes/no" questions tend to indicate a verb in focus.