I don't remember which forum it was, but there was an answer that went like this: "If you have to ask, then it's probably not a good idea to try to sell it." Also, parody and satire is a fine line. MAD magazine can get away with it because that is obviously meant as humor. If you sell a "Snope" character (obviously a version of "Snape") with the sole intention of making money, where is the "humor" to classify it as parody? But, "close enough" usually works for most things, especially in the 3D world. Many companies own the likenesses for a specific use (you can't make and sell a movie using Harry Potter characters). But a digital version for use only in Poser? Definitely a gray area.