If you go by Disney's backstory, Disney Springs is set in present day and was an old Florida springs town that (as seen by the already opened or under construction restaurants), in simplistic terms, showed a love for different modes of transportation, much like Walt Disney himself. The story continues that much of the town was re-purposed to be a bustling dining/entertainment complex. Really pretty dumb, but you get the idea.
So honestly, anything could go into Disney Springs if they want. However, I think they are trying for either period establishments or higher end establishments. I mean, even the Cupcake ATM place has more class than a In 'n Out.