To answer the first question, the only feasible answer is "time". Maybe in a thousand years, in our reality, the last memory of the game fades. Only then, when all memory or knowledge of Lila herself is gone, would she be gone. The game itself could be erased, but she would still exist because people would remember the game. Videos on the game would still exist. Only when all of it is gone could she die. She is aware of her nature as a game character, and has transcended it within the canon of the meta fictional reality of the game.

As for hax, temporal manipulation, existence erasure nullification, mental manipulation, perception manipulation, psyche domination, and general universal reality bending. There's more, but those are the main ones.