In fairness to Leanne, that challenge (the wedding challenge) was probably one of the most unfair/ridiculous challenges in top chef history. Which was saying a lot.
When everyone was presenting their menus, no one had any idea that they 24 hour prep, until after it was announced LeeAnne won the quickfire. That meant the menu, the cake, the service, supplies all in 24 hours. I don't think anyone could have saved their menu regardless who won. Not to mention, there were things like (LeeAnne , had fresh salmon in her menu, but they only sold frozen in the store). Or stupid stuff like be given spoons and bowls that all had stickers on them, so everyone wasted a couple of hours peeling and washing off stickers.
There is a reason why Leanne worked behind the scenes, and there was a very different modified wedding challenge in season 4.