Unless I'm misunderstanding something, I don't see where there's a savings for you, as a buyer, in leaving out the broker. Typically in a real estate transaction, the agent's commission comes out of the seller's proceeds. I suppose you could hope that the seller would be selling for a lower price, since they don't have to pay commission in a private transaction, but I think that's a bad assumption. I wouldn't sell for a lower price in such a situation, I'd just be happy that I got to keep more of the proceeds.
At any rate, even in a for sale by owner situation, the contract would still have to be submitted to Disney for ROFR, and you wouldn't get your hoped-for savings if the price is low enough that they decide to claim the contract.