Argh wow! The Spanish cover is insanely wrong and who in the world are the two girls on the cover because they aren't the sisters Grimm (it could pass of as Red and Briar? Maybe? Possibly? If you squint?)
I actually quite like this cover though the colour is wrong (it looks like it should be The Unsusal Suspects):
I know right! It's weird that those covers were in use for that long and, ugly as they are, I now really want to see what the other 8 books look like. But yeah, I agree they were probably used as temporary placeholders because they are not available anywhere.