Honestly I can not remember, but I do remember feeling the site was some how affiliated with DMC ... maybe an official website for the DMC anime that's been since taken down? Anime's are known to have character spread sheets for main/reoccurring characters.
I'm 95% sure those are official, but I have no proof to validate my claims. So I'm sorry I can't say anything more than that.
If it helps, those artworks of Lady and Trish are very identical to these official concept sketches. The poses for both Lady and Trish in the group sketch in the lower right hand corner are near identical to the supposed final products in the links you provided.