Jotisz - the bluesuit is particularly plain - I'd imagine some of the others would need quite a bit more detail to work - but the process would be the same for other characters and armour models etc. If a greyscale texture can be made of each, colours can be layered in easily, then extra details added on another layer and so on.
Note that the Blender .x export itself seemed slightly garbled when I tested it, but the fbx one was perfect and easily converted. I'm still unable to import any of the existing rigs into Blender properly unfortunately, but will continue to try things every now and again. It would help a lot with speeding up the animation if our Blender specialists could access the existing animation work and rigs.
Johnnybravo - writing the lighting settings is one of the bits I'm really not very good with, so that's better left for someone else. I'm okay at positioning lights in a 3D program and adjusting in real time, but writing text, then loading to see what it's done is something I'm not familiar with. Alsol, the floor shadow appears correct - I assume this would move if we moved the lighting?
Grain / noise is probably right - it could be finer detail, but it's only really going to look like grain in game at 100% zoom (I tried a denim texture on some model, in game it was merely a slight grey noise). I suppose the question is whether we simply "apply noise" to the texture, or apply fine details which will ultimately only look like noise. I think I'd have to test both to see what the difference was visually.
I remember Karpov's test stuff on specular - and it worked pretty well. It would need some fine tuning to match sprites, but I think it's possible. I'm trying to think if there's some way to work out where / how it should be. The projection painted stuff gives us a bit of an indication, but otherwise it pretty much involves studying lots of sprites. Depends how perfect we want it. It might be as simple as a slightly tweaked greyscale version of the texture to be applied to the model, then brightened or darkened as a whole depending on the material it represents. Again, won't really know until it's tested. Regarding existing textures, eventually a lot of them will probably want redoing, depending on how sprite-accurate we want them to be. I know the ones I did certainly have a lot of painted on lighting, as the lighting effect we were using at the time was a lot further from accurate, and they needed a lot of this to look even slightly "in-game style". The lighting in game is better now, so a lot of that shadow is redundant.
Ultimately, my main thought is simply to keep colour, detail and shading elements on separate layers in layered source textures. We get them as close as we can by any means necessary. If / when we improve lighting /normal mapping etc, we alter the relevant layer. Should be easier to "mass adjust" rather than "mass redo" everything.
Nastykhan - You can name them however you like really, but they do need renaming specifically when they're put into game along with other models and textures. Your suggestion sounds a pretty good idea to keep track of things in progress though, but I'd suggest using 2 or 3 letters per person.