Not bad.
I liked your second one (robotic?).
The other ones are okay.
Good job.
Superslice: To put them on you have to:
1) Buy a head texture. (Price can vary from 1k-20k depending on the type of head texture that you may be buying.)
2) Save the image that you want as your head texture.
3) Upload the image onto your head texture.
4) Activate your head texture.