Barry,
As you stated the constitution doesn't say that it has to be a 8 man bracket for such and if I was the tournament director I would make it a round robin. That is why I raised the question at the state meeting two years ago about rebracketing the day of the tournament when you had scratches that brought a bracket down to a 4 man bracket. It was the opinion of the body that anytime after the seeding that a bracket drops to 4 or less wrestlers that a bracket WILL be rebracketed to a round robin. I don't agree with that opinion but I would abide by the rule of the body. Therefore, if I'm the tournament director, in order to prevent the possible rebracketing the morning of the tournament I would put the 5 wrestlers in a round robin.