Y'know, that's actually a pretty good question. I remember a long, long time ago, around when the author room was still pretty new, I saw one of the author's messages had an option to look at old concept art. One of them included Uro's, so it's safe to say they at least had some involvement in it. I'm pretty sure it was Twenty/20, especially seeing as how he's the current director of Yume 2kki, but don't quote me on that.
If I ever find those files again, I'll post them here. Damn, I really wish I knew moonrunes though.