mind if we change your main cress's spread to 240 HP / 12 Def / 40 SpA / 216 SpD? More HP is usually better for overall defense of Cresselia, and 216 EVs in SpD gives it a jump from 383 -> 385, which makes the spread more efficient. Even with reduced Def EVs and SpA EVs, it still survives a Dark Gem Crunch from TTar and 2HKOs Hitmontop / Virizion / Hariyama with Psyshock.