THe level of detail of a model is limited to what Gamestudio and the user's computer can handle. You CAN make a model with a few hundred thousand polygons and make it really life like but you can't use that in Gamestudio. You have to try and use polygons sparingly and make your model look as nice as possible with proper skinning.

Making a model that can change shape height, colour etc would be partially done with different models (for a different gender you just use two different models) and other options are mostly done with scripting I think - but I am no expert and have never done this myself.

Things about CInema 4d: CInema 4d is a 3d program meant for creating high quality 3d animations. It features nice tools to make modelling much easier and allows you to make animations using bones (and IK). As far as I know you should also be able to export the animations to MED and thus avoid having to do the animation in MED but I have never done this so I don't know. Skinning should aslo be possible to do in C4D with the "3d Photoshop" - Bodypaint. I haven't used it but it should make making a good looking model easier.