If you go back through the rest of the comic you can see that Nick has designed each of the Toa's masks to look a bit more like their base design, so all of Tahu's masks look a bit like a Hau while all of Gali's masks look a bit like a Kaukau.
example: page 75, Lewa's Kaukau has fairly strong Miru elements.
I actually reckon it's a cool way to make the toa feel distinct from each other even when they are using each other's masks.
Hope that Takua and Pewku will be alright with the tundra. Tahu seems to have an inkling that things aren't going well for "lone wolf" brother, either that or he's concerned for him; nice way to contrast his previous antagonistic attitude.