I've got test alpha channels for all creatures now except for the construct, because it has got an environment map as texture and I'm not sure how I can properly overlay it with another texture. The team colors on some creatures look pretty good already, but on others like the dwarves they don't seem to fit very well and are also not very visible. And this shimmering effect is probably too strong, because it makes the colors almost white sometimes. Red team colors, for example, look pink most of the time.
I begin to think that it could be better to use only symbols under the feet or over the heads like in DK, that also show the level and health of the creatures, instead of painting the colors on the textures.