Here are my circus cards:
My mythics are a little weird, I know.
Lion Tamer seems a little out of color pie mechanically, but flavorfully, I believe it fits. His control over the cats isn't magical as much as it is nature-oriented. He befriends them instead of dominating their will. (He might actually be a Druid instead of a Shaman, now that I think about it.)
As for Tibalt, I think emblem manipulation is a fun mechanic that hasn't been explored yet. There are some weird rules interactions that might need to be fudged, but I would say the ability is pretty grokkable.