In Illustrator, what happens if you turn off the GPU Performance preference?
If the image is rasterized in Photoshop and you convert the image to RGB, the colors would not be CMYK anymore. You could also export as PNG from Illustrator if you wish. PNG only supports RGB and grayscale. I'm assuming the graphics would need to be rasterized in After Effects anyway, unless you are using them as masks.
Not sure what Overlord is...
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