So there are five coven roles:
Coven Leader - Can control a player at night - as far as I see no one has claimed being controlled, so coven leader did not visit anyone?
Hex Master - Could have hexed someone and visited
Medusa - Is not able to visit until they get the necro
Necromancer - Doesn't visit people, uses a dead persons role against someone
Poisoner - Is able to visit people, so either the poisoner visited someone who is immune or they don't have a poisoner, as no one died
Potion Master - Could have used a revealing potion
With no one claiming to be controlled, are we even sure coven visited 3 people last night?