How about this:
>Trevor uses rare, strong mons that are always only available at points in the story after you've faced him first; he battles you, but also rates a) your dex quantity, b) your team variety, c) whether most of your pokemon are caught, traded/given, or evolved, and d) your EV distribution
>Tierno uses dance moves and/or pokémon based on dancers without said moves; fights using stat-modifiers and elaborate arena modifiers, baton-passes, and meta-game famous "spinning" moves (rapid spin, whirlwind, dragon tail) to break down your set-ups
>Shauna uses a team based on her starter, but with abilities, items, and moves designed to negate your attacks (wonder guard, magic guard, magnet rise, fly, disable, taunt/encore, attract, evasion/accuracy)
>Salem/Serena has a well-rounded team with a sweeper, some status moves, and a couple of walls
>Defeating each rival at different points prompts in-game dialogue referencing how online-play differs from in-game battles, written in such a way as to hint to kids that there are deeper strategies than "use super-effective moves often," and to draw attention to how they were attempting to beat you
>Rivals compliment you for using stat-modifiers, "combos," and distribution of stats, type coverage, and moves, and passive-aggressively congratulate you if you win based on strong moves/stats alone
>Your play-style during the story tells you which rival's strategy is most similar to your own. This evaluation can be modified later via post-game re-matches, and appears as an icon on your online profile
