No longer a hostage to the 2017 season, Mets officials Monday began an offseason that features a lengthier “to do” list than normal. And near the top of that list is finding a new manager, following Terry Collins’ resignation Sunday after seven seasons. Indications are general manager Sandy Alderson will begin interviewing candidates this week, and may first attempt to speak with Bob Geren and Alex Cora, before both become ensconced in the postseason with their respective teams. But it was unclear as of Monday whether Alderson had yet requested permission from the Dodgers and Astros to interview Geren and Cora, both of whom are on the Mets’ list of early possibilities to replace the 68-year-old Collins. Geren is certainly familiar to the Mets after spending four seasons as Collins’ bench coach. The 56-year-old Geren left the Mets following the 2015 season to become the Dodgers bench coach in large part because he wanted a return to his Southern California roots. Geren’s previous managerial experience came with the Athletics from 2007-11, but that tenure included turmoil: relievers Huston Street and Brian Fuentes both publicly criticized Geren for a perceived lack of communication. As Collins’ top lieutenant, Geren was largely viewed as well-prepared. His thorough understanding of analytics and how they applied to the game appealed to the front office and won him respect among veteran players.