Are any of them going to actually be designing, or is it just taking the 'signature course' thing to its absurd conclusion? They want to sell massively overpriced lots, so they get together all the big names for the age group that is most likely to have the cash to buy them.
From the standpoint of the success of this, who actually designs the course (probably one of Nicklaus' guys, but who knows) and its quality is mostly irrelevant. This is a real estate driven course, sold courtesy of the big names, and even if it is a terrible product they'll probably presell most of the lots before anyone is able to determine how good or not good the course is.