It is very likely the two cards will be brand new, as is usually the case with these Trainer Kits. No new Alolan Sandslash and Alolan Ninetales have been announced for Japan yet.
Like all Trainer Kits, the package will come with two 30-card decks, two how-to-play guides, a 2-player mat, damage counters, Special Condition markers, a coin (of one of the two Pokemon), an illustrated deck box, and a PTCGO code card.
A Trainer Kit is meant to teach new players how to play the game. It includes simple cards that are easy to understand and use.