Yeah
Climbing beans would be better - the idea is the sweetcorn provide support for the climbing beans, and shade for the squash. The squash provide ground cover acting as living mulch + prevent evaporation. The beans fix nitrogen for the squash + sweetcorn. Hope that makes sence.
Space the sweetcorn as normal (as a block), but miss out enough in the patten to place your pumpkin + squash (make them quite even)
Then plan the beans at the base of each sweetcorn.