The ge64 models are a good starting point, but because they are so low res and lacking in detail, a better concept is needed. For example, for all of our main characters, we pretty much ignored the game models, because as reference, they are pretty much worthless. We looked to the movie to provide all of that detailed information so that we can then incorporate that into the models.
The same thing applies to the generics. We look to the game models to get a sense of the character, but then look to other references to actually create the models. We refer back to the game models to make sure we keep the same style, but that is really the only way they are useful. For the ssf concept, I researched a bunch of different snow soldier uniforms and pictures, as well as snow soldiers from other games. I combined the elements I thought fit the character best to create a rough idea of what the character would look like.