Been trying this in Twilight Break. Ahkmou's tactic for stone manipulation is seeking out weak points so that he can spend minimal energy breaking down structures. In fights, he relies on surprise stone pillars and lots and lots of walls. Meanwhile, Hewkii is all about projectiles, kicking and throwing boulders like he used to with kolhi balls, and he tends to go for athletic dodges rather than firm defenses. And Pohatu, is described as having a bit of a cross between them, where he works with the strong and weak points of rock to move and sculpt it, rather than break it down, and his rock kicks are deadly. He also uses his mask a fair bit more in a fight than either Hewkii or Ahkmou use theirs (though the latter has the excuse of his Rau not exactly being useful for combat).
Jaller combines a lot of what he's seen from Tahu and what he's learned from Vakama, switching between unrelenting fire and precise heat.
Hahli is nonstop beserker offense, never giving her opponent a chance to rest or regain their footing, while Gali has always struck me as one who avoids going all out unless she has to, preferring to use what she thinks is just enough power for her opponent (hence why her flooding an island to fight Icarix is so surprising because that was what she ultimately concluded was necessary and wasn't something we had really seen her decide to do before). Nokama always struck me as combat avoidant, preferring words and supportive measures of her team instead.
Onua is a gentle giant, who very much has that preference for other measures besides a fight, but when he does fight, he goes for unsettling and disrupting opponents; earthquakes, tremors, and sudden fissures all get used to keep his opponents from having stable footing. Whenua is an analyzer, and while he may seem similar to Onua in not charging into fights, it's because he's picking out how best to strike, often finishing a fight in one sudden cave or ground collapse. Nuparu excels in fighting above ground, going for traps by using earth to bind and immobilize foes; his mask along with his inventive tools and weapons make him great at ambushes and being unpredictable.
Matau and Lewa are exceptionally similar, with very energetic and often reckless movements that rely on speed and bringing them in close, all the while using their wind to directly attack. Kongu, however, is much more a distance fighter; he prefers using equipment and weapons, and his use of wind is more subtle to guide his shots. Unless he's sneaking behind an oblivious toa of shadow, in which case he just brings a concentrated hurricane down on their head.
Matoro was definitely the conflict avoider of the Mahri, and his use of ice was much more in support of his team or to assist in escapes. Kopaka, like Tahu, just goes in with overwhelming force (though he's a bit more discretionary of his targets) and utilizes cold almost constantly, even outside of combat. Nuju was, like Whenua (much to both of their chagrin) an analyzer, employing precise targetting and timing to get his attacks through defenses or to trip up opponents with sudden slips or freezes.