Perhaps the color replication on my monitor is playing tricks, but I could swear that I see creamy patches on her cute little face, particularly on the chin and mid-face. As you said, it could be the lighting... but from the way I'm seeing it, it's most noticeable to me in the second picture.I'll take that dare! Purebred Russian Blues do not have cobby heads or big round eyes. They're rather lithe kitties. This kitten looks closer to a British Blue if she resembles any purebred.
Most solid-color kittens have some ghost striping. Sometimes if the light is right, you can even see it when they're adults. However, I think she may be a blue tabby because the stripes don't look "ghostly" enough. It will become more evident as she gets older. I don't see any cream spots so I don't think she's a torbie. The lighter area around her mouth just looks like shading.
She's soooo cute! I love her little blue nose!