Facade has 140 BP when the user is aflicted with status. With STAB, that's 210. Orb'd Swellow exists for a reason; Facade is deadly in the right poke's hands (... or, in this case, wings).
Oh, and for sake of being a correction-happy douche, X-scissor doesn't increase critical hit ratio. :P
Sing has 55% accuracy... Not the best move. In-game, it could get you out of a pinch, though.
Slowly but surely, I've been working on rewiring my current uber teams. I'll post something eventually, rather than annoy everyone with insignificant corrections.