Not sure if anyone cares about my input on the situation but imo Vivillon has little use for any Hidden Power. It's pretty hard to justify removing one of Vivillon's main moves (Sleep Powder, Quiver Dance, Hurricane or Bug Buzz) for Hidden Power. But that's just me.
Though if you really want to breed for Hidden Power then bred for Fire/Ground/Fighting, help against Steel types that can wall Hurricane or Bug Buzz. But even then it's so weak to remove one of Bug Buzz/Hurricane. Also Hidden Power Water is really bad for Vivillon, it doesn't even help again Rock/Fire types like you think. :o
252+ SpA Life Orb Vivillon Bug Buzz vs. 252 HP / 0 SpD Arceus-Rock: 140-165 (31.5 - 37.1%) -- 81.3% chance to 3HKO
252+ SpA Life Orb Vivillon Hidden Power Water vs. 252 HP / 0 SpD Arceus-Rock: 125-148 (28.1 - 33.3%) -- 0% chance to 3HKO
252+ SpA Life Orb Vivillon Hurricane vs. 252 HP / 4 SpD Arceus-Fire: 172-203 (38.7 - 45.7%) -- guaranteed 3HKO
252+ SpA Life Orb Vivillon Hidden Power Water vs. 252 HP / 4 SpD Arceus-Fire: 125-148 (28.1 - 33.3%) -- 0% chance to 3HKO
Also like everyone else said compound eyes is a way better ability, 91% accurate Hurricane and 97.5% (I think, lol) Sleep Powder goes a long way.
Though if you really want to breed for Hidden Power then bred for Fire/Ground/Fighting, help against Steel types that can wall Hurricane or Bug Buzz. But even then it's so weak to remove one of Bug Buzz/Hurricane. Also Hidden Power Water is really bad for Vivillon, it doesn't even help again Rock/Fire types like you think. :o
252+ SpA Life Orb Vivillon Bug Buzz vs. 252 HP / 0 SpD Arceus-Rock: 140-165 (31.5 - 37.1%) -- 81.3% chance to 3HKO
252+ SpA Life Orb Vivillon Hidden Power Water vs. 252 HP / 0 SpD Arceus-Rock: 125-148 (28.1 - 33.3%) -- 0% chance to 3HKO
252+ SpA Life Orb Vivillon Hurricane vs. 252 HP / 4 SpD Arceus-Fire: 172-203 (38.7 - 45.7%) -- guaranteed 3HKO
252+ SpA Life Orb Vivillon Hidden Power Water vs. 252 HP / 4 SpD Arceus-Fire: 125-148 (28.1 - 33.3%) -- 0% chance to 3HKO
Also like everyone else said compound eyes is a way better ability, 91% accurate Hurricane and 97.5% (I think, lol) Sleep Powder goes a long way.