-- Mayim will take over from January through the end of the season
That's not exactly what he said. Direct quote from MD, "When she takes over from Ken in January, the current plan is to have her host a couple of new tournaments as well as the Jeopardy! National College Championship and as many weeks as she can manage with her other primetime commitment to “Call Me Kat.” We know you value consistency, so we will not flip flop the hosts constantly and will keep you informed about the hosting schedule."
So they'll have longer runs than a couple of weeks here and there, but "Call Me Kat" is in first position for her and they're still accommodating that schedule.
Also he dropped the idea of a Jeopardy! Masters league in primetime or streaming as his pet project. That has JenKennings written all over it for the host slot. Perfectly made for ABC or Hulu.