Screw it, expediting the process since I know exactly what the changes are gonna do.
Since I know you love your patented critkill method, it's time to start planning around that. Even if ALL FOUR attacks crit, Regice still survives! GO ME!
Ra's: Brick Break -> Drain Punch (both Regice)
If Icy Wind, change that action to Wide Guard. Do not activate consecutively.
Phoenix: Rock Slide -> Hi Jump Kick (Regice)
If Regice uses a successful P/E move A2, change that action to Feint and push back
If Gravity is in effect when you would use HJK, change that action to Close Combat
Derpy: Slack Off -> Yawn
If Safeguard, change A2 to Chill
If Regice is behind a substitute when you would attack, change that action to Chill
If the changes are ANYTHING BUT Walrein faints, Regice gains 3 HP, and Rev comes back in, can you inform me?