I don't know that much about the series, aside from all the horrible shit my moots tell me about the unhinged fanbase. But, if I had to give Elio a designation, it would be <Ultimate Argenthusiast>.

Also, he would definitely be a survivor - doing his utmost to contribute to the group after becoming familiar with the game's rules, since his life is at risk. Some of his skills include being a frighteningly skilled liar, having a silver tongue, and being keenly perceptive via his precisionist mentality - all of which amalgamate into a deadly combination when it's additionally mixed in with his incredibly high charisma and his normally altruistic, friendly, and somewhat easygoing nature. He would be the last person you'd expect as a mastermind... which is ironic considering he would also be a perfect fit to be one.

In terms of execution, it would be something related to silver - given his epithet. For example, molten silver being poured on him or being dropped into a vat filled with it, swiftly yet painfully killing him as his body becomes a silver statue in the aftermath: essentially transforming the now-dead contestant into what he "loves".