coming from someone who knows a ton about bionicle MOCing...

they're nice, but a little cluttered. too may pieces some places, not enough others. i'll be giving a moc by moc critique. this is constructive criticism, please don't take offense

they have good potential.
I always appreciate constructive criticism. It would have to be really harsh for me to take offense, and also not contain any positives.
Matoro:
my favorite by far. the only thing i have to say about him is that the heads on his shoulders are freaky o_O and also aren't toa of ice white? but otherwise awesome

Yeah, I recieved the same kinda stuff on BZP. I've since removed the heads and added white, but I may remove the white as it doesn't look that great...
jaller:
really nice as well, but the colors are a bit scattered. red black and orange are fine, but then there's some silver and trans orange as well that visually distract from the MOC. personally i think he would also look better without the toa metru chestplates on his heels. Also, his arms look like they should be bulked up a little bit more. i love his shoulder cannon : 3
I'm removing the black and trans orange from the MOC (including the metru chestplates on the heels (these were only there to keep the feet from sliding off)). I liked the cannon too, but it was really hard to put into position.
kongu:
first off, posing fail. i can't see much of his torso or his right side, which looks interesting, from what i can see, in any of the pictures. past that, legs not being symmetrical don't look that great, and the red and silver clash - maybe get rid of one? arms winder than the legs also looks a bit odd.
Sorry about the pose- I only realise now how much the weapon blocks his torso. When the gallery is public you'll be able to see more of him. I won't be changing the asymmetry of his legs, because that was one of the main focuses of this MOC (it relates back to his split Inika mask). I'll be removing some of the red and replacing it with silver, most likely. I'll leave a bit on, but mostly for his weapons.
hahli:
she looks very nice, feminine. but loose the orange, it doesn't look good on her. maybe if you replaced the light blue limb peices with jaller inika trans orange it would.

also toso's a little too thin
I originally tried to have a theme where each of the Mahri (minus Matoro and Jaller) had some trans colour on them which reflected their heartlight colour. For Matoro I didn't add any because he died, and Jaller was really weak in Mahri Nui because he was completely out of his element. Apparently this whole theme didn't go over well, so I'll be removing most of the trans colours (as I've already said in the upper comments to your comments).
And yes, the torso is too thin at the bottom, and too thick at the top for a female (as a member of BZP pointed out to me). I'll have to go full custom for Hahli to get better female proportions.
hewkii:
his head;s on backwards o_O
and loose the green, it clashes horribly. the arms also seem a little short for his torso and legs.
The head is on backwards because I never liked the original forward facing mask. I always thought it looked better backwards. I'll get rid of green, except for the heartlight. Arms may just look short in the pictures, they look fine to me (they definately aren't monkey arms like the original sets...)
nuparu:
not a big fan of mixing gunmetal and silver, but it looks ok here. i see what you were trying to do with the green, but it needs either more or less, not quite sure. in his rear shot it looks like he has a blade on his back? if so can we see it? and i am personally not a fan of asymetrical claws, though it looks on here
Green will be removed. The back has a shield and the blade is something that I just thought looked cool, I guess it's like a fin or something.
The right hand isn't really a claw, more a hand attachment that allows Nuparu to be better engineer (as he was as a matoran). I'm replacing the left claw with a larger one because of a post on BZP. This claw is an actual claw for combat.
so, in conclusion, i think these guys are pretty nice - but need touching up. visual clutter (including blue pins, the bane of my mocing existence) make them not look nearly as nice to me as they should. good job. i'd like to see more from you

Thank you for the indepth C&C! I really appreciate it, as it allows me to improve my MOCs. Along with the above comments I will try to get rid of blue pins, but I don't have any black friction pins, and the light grey ones don't have friction pins, which make them not as useful, unfortunately.