Well, for the one character, I was thinking a Plantlife Toa with a way to access a bit of alternate powers, such as either venom, or maybe a swarm or small insects. But, because I didn't think of, like, what his life was as a Matoran yet, I'm not sure what kind of mask would really fit.
The other character idea is a Ko-Matoran who actually hates the cold. I was thinking that, due to his past, he'd likely get a Mask of Psychometry, but as for weapon, don't even know. I should probably get the OOC up somehow.