Gentlemen,
I personally and I am sure lots of other experienced flight crew update secondary flight plans on a regular basis with turns towards waypoints for the closest suitable diversion field.
There is nothing abnormal about this, it is called AIRMANSHIP.
Alright goodnight, is a STANDARD goodbye greeting at handover. NOWHERE is it mentioned that the frequency was omitted in the readback.
Greetings,
Despegue, an ACTUAL Airline Captain.