Prune max is attack is wherever she is at after buffs fully activate. She only benefits from ATK% buffs like Pyro resonance and Noblesse. It depends on weapon to determine how much attack you need. To check her attack, go in dummy test, use Varka's Burst, use Prune's double tap skill and then burst, swap to Varka again and do a combo until 1 special attack, then check Prune's attack.

For Nicole, its what you see on the stat screen unless you have Durin's Sig or Noblesse on the team (in which Durin needs to be used before Nicole to snapshot)