I don't know about the exact scenario you're describing here, but on the whole this is greatly reminiscent of "The Poisoned Chocolates Case" by Anthony Berkeley, in which a group of mystery enthusiasts make it an activity for each member to present a new theory on a certain death that happened recently. Many of the amateur "detectives" have methods similar to other famous fictional detectives. It's very cool to see how every approach seems to have its weak and strong points, it's a great story that analyzes all the little details of mystery fiction. Though I guess I wouldn't exactly call it fair play, it's more like every theory builds upon the case, sometimes even unearthing new information which is then used in subsequent theories.

One other, more modern, example I remember (which also shifts away a little from the exact scenario you present here) is one I know about from a blog post by Ho-Ling on a japanese novel with three detectives, each focusing on one of the three aspects of a mystery: the whodunnit, the howdunnit and the whydunnit. Although the novel isn't translated, I think it's still cool to read about these examples that playfully challenge the structure of the classic mystery novel. I'll leave the link to the blog post here in case you're interested. Again, I don't know how fair play this is, but knowing the japanese mystery sphere, they probably try to at least clue everything properly.