And who would take over as head writer at SNL? The highest ranked writers under Meyers are Colin Jost and John Mulaney. Both receive Writing Supervisor credits in addition to their writing credits, which Seth Meyers also had before becoming co-head writer in 2006, so one of them would be a natural choice. Jost has been there longer — he started in the 2005-2006 season — so he may be the natural successor.
As for taking over on Update if he were to leave the show altogether, Mulaney has appeared at the Update desk a couple of times, although not at all in the last season, so it would seem like he’d at least be considered. Or it could be a castmember; a younger, underutilized player like Nasim Pedrad or Vanessa Bayer could be a fun choice.