How to make Enemies

[Obliviator27]

What you're asking for is a huge request. Making these things isn't as easy as you may think. I've been playing with 3d modelling tools myself for probably 6-8 months now, and I still don't have the skills to create my own enemy. You need to have artistic ability, something that I certainly don't have. Creating both of what you need would take a long, long time and much dedication.
For the time being, I would recommend you stick with the default enemies. The most "editing" you could do to the Grunt or Brute would be a re-texture, and even that would take time.