Lip-synching skits are pretty much a no-no. They get boring and very awkward. I would recommend writing a skit with your own dialogue. It's more work, but the audience and judges will appreciate it a lot more.
Matsuricon/Glass City Con/Youmacon Cosplay: Armin Arlert/young Armin (Attack on Titan); Ultimate Madoka (Puella Magi Madoka Magica); Fem!Masky (Marble Hornets)