Some nice work here Liz :] I like a lot of the female poses, I would say that some of the anatomy is a little off from time to time and be careful you don't keep the poses too rigid but other than that the contrast and colour of the characters are very nice. Keep it up!
I'm absolutely speechless with your artwork. It looks like you've improved greatly with all character sketches especially with anatomy and proportions as well as ideas for character designs. It would be good practice if you could draw expressions on characters' faces to bring them out to us. Otherwise, keep it up with a fabulous job!
that last character kind of reminds me of Sarah Conner from T2. Nice studies! Good to see your pushing yourself more in other directions aside from character designs, since I think your characters are already looking sweet.