Typically the buyers. If the sellers did any work that required permits, then that should be the exception as it would be disclosed in the sellers disclosure.
Open permits can be a little costly but there are specialists who can help expedite the process, typically old employees of the city. If you need one, drop me a line.... more
I am sure you are asking a question that is not answerable in this forum or likely area of expertise. While I have been involved in this area, there are to may variables to give an answer.