...Whimsicott learns Beat Up? o.o
Well, anyway, I've heard lots about this strategy and briefly played around with it myself. However, I found Absol to be the best option outside of Terrakion. Higher attack, Justified and resists Beat Up, still has access to Rock Slide... In truth, the effectiveness of Terrakion comes from its getting STAB on the multihit move, so there may be no real effective substitute. And yet, Absol can still do a number. I don't see any reason to use Gallade over it though.
Also, why Girafarig?