Shelob, the cat of Sauron

[Iarephelion]

I'm not sure if this is the right place to post. If not, feel free to delete/redirect me. I've been reading the Tale of Tinuviel (BoLT2) and can't stop wondering about Chris Tolkien's treatment of Tevildo. I get the impression that he believes Tevildo to be an earlier version of Sauron, later deleted from the story as the legend of Sauron was developed. I am reminded of the children's song "Ring a ring of Roses", a simplified version of the effects of the bubonic plague. Bearing in mind that the Tale of Tinuviel was told to Eriol by Veanne (a child), is it not possible that Tevildo was a simplified version of Sauron, part of a tale told to children in a manner they could more easily identify with (animosity between cats and dogs). Or is this merely wishful thinking on my part? By the way, this has rapidly become one of my favourite tales concerning M-E. Anyone able to educate me further?