Legality depends on the tournament format -- Yue, the Moon Spirit can be legal in some formats and banned or restricted in others
Most stores will be running these events with rolling pairing, meaning as soon as you wrap up a game, you'll be paired against a new opponent
Black Lotus can help you cast a high-cost win condition and Shivan Dragon can save you if you need a flying creature on the battlefield to stave off an opponents horde of flyers
Unfortunately, because all of the Pokmon and a majority of the trainers from the Pikachu deck (and the other two decks as well, actually) have D and E regulation marks, they are no longer playable in standard format, whether its on Live or at in person tournaments
Pearl Medallion and Idol of Oblivion
It gave both sides influence without giving either one total control