The M.E. Church is Methodist-Episcopal. I don't know where any records might be. My gr-gr-grandfather was a M.E. minister affiliated with the Northwest German Conference of the M.E. Church. He lived and pastored in Charles City at one time, but not in the time frame you are searching.
Also, St. Charles Township and Charles City are two separate entities in the census records. You would want to check both areas. Sorry I couldn't be much help - perhaps someone else can. Good luck.