The multiple hits on a single attack come from the effect itself
The moment you tap out, that could be the end, especially if they have a Wonder up their sleeve
(10/4/2019) If an effect allows you to cast a spell without paying its mana cost, you can't choose to cast it and pay unless another rule or effect allows you to cast that spell for a cost
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
The only time you cant interact with a background card is if its acting as a second commander and is still in the command zone
And being able to toss a snack at an opponent when you take their Orcish Bowmasters on the ultimate, which you can do on the second turn, is just extra obnoxious