Ancalagon
Dusty Dragon
1: If you have the time to cast, rest, cast, rest, cast, rest.... you could just take a long rest instead.
2: Walking into a dungeon with a few extra HP in your back pocket won't break things.
Just let them be "clever". You can always add an extra monster if things are too easy.
1: This is something that could be done in the day, and head out in mid afternoon (this assume there is no big time pressure, of course). Why would the warlock take a long rest when all she needs to refresh her powers is a short one? Create 2-3 potions, meditate an hour, do it again...
2: Well, that could easily be 6-10 healing potions - it's a bit more than a few
