I see you (and I) have the same belief that this has been a job interview process, not necessarily limited to the VP slot. At worst case he’s got his Cabinet staff pretty much selected (or de-selected) and in reality those positions are more influential than the VP (except in the case of succession).
Anyone who doubts that needs only consider the number of times the Constitution has been trampled and evil deeds donw by say, Eric Holder, than by Joe Biden.
I think Sessions or possibly Huckabee.