Thanks for the reply, I sure hope the lorebook can clear up the questions as to Eorzea's calendar.

The Thursday line came from the description of a WVR levequest. Not sure which one, but you can find it at Eustace in the Quicksand. The levequest description appears to be written as if it's being spoken by Roarich, and the line, IIRC, goes "Master Gegeruju is in love, it must be Thursday." I suppose it's just a throwaway reference, but a bit of an odd one to make.