Can I be taken advantage of and how do I protect myself?

[Corey Kenney]

I have a house under contract that is currently zoned commercial and the purchase and sale are contingent upon the property being rezoned a.k.a. (land use variance)residential. Normally it is the owner of the property that needs to make a case to the board but it does specify that it may be someone else with interest in the property with the owners consent. My question is If I pay to have a lawyer work with me and pay the engineer/ architect to draw the plans needed couldn't the seller turn around and list the property once they memorialize that new approved use. Yes I have a contract and yes I should get my EMD back but what is preventing them from selling it now that the value has increased dramatically. I assume I could file suit and hope to get a judgement bit that's more of my time spent with no return or do I not have a leg to stand on. Do I need to have an addendum that specifies the seller can't screw me or is it implied?