The whole message seems really suspicious to me
For one thing, why would a legal person specifically mention lyra when its name isn't even copyrighted, and even if it was because they were offended, why did they ask to get the rest of my plushies taken down too?
If it was because I was selling them, why was I the only one targeted and why was there absolutely no mention of my previous ebay auctions?
And as someone on reddit pointed out ( http://www.reddit.com/r/mylittlepony/comments/wpx4a/so_yeah_this_happened/c5fg0jl ), the citations are completely irrelevant and have nothing to do with copyright, and the fax number doesn't even match the one on their website.
and since other people in this fandom have gotten similar things in the past, it probably wasn't very difficult to just spoof up an email that looks realistic.
tl;dr it looks really fake to me