If you give a goodberry to a unconscience person do they get 1 hp?

A Night Hag is in a coven with two Sea Hags. Do the hags have access to shared spellcasting?

Does Mind Blank spell protect from all the effects of Feeblemind spell?

Ranger-Hunter; Multiattack feature: How does it work with spells with “The next time you hit a creature…”

Does the caster immediately knows that the target makes his save successfully?