What about copyrights?

I would retain the copyrights myself, since I would be the author. This isn't ghostwriting, where I'm taking a plot that is already laid out and putting it into words, but taking a central idea or image ("a story of a wedding with an apple tree in it" or "A story about a boy with a blue eyebrow" or somesuch) and writing a wholy original story around that idea.

However, if you and your friends want to write that story idea and keep the copyrights to yourselves, I wouldn't mind helping you write it, and giving feedback... but that's a different service than I am offering for the auction.