Quote from @Jerry Cox: Quote from @Michael Dumler: @Jerry Cox, be mindful of your dates and contingencies within the binding agreement if you go under contract.

And never being “at risk” is it even sufficient to legally bind a seller?  

First, the tenants signed a legally binding contract and do not just get to walk away on a whim.

Jonathan, I am not asking for legal advise, I said advise, without the word legal. 

“Broker” is a legal term that often requires standardized coursework and a state license. 

Is there any legal action one can take or is it just a lost cause?

I won't be able to make the cottage legal rental without living in the primary home myself.

This is something their screening probably would have caught, or their system would have a legal procedure to deal with it.

Hi @Heather Bailey something to consider with this is legal mother/daughter may not mean legal duplex. 

They can limit what property owners can do, including house hacking.Even if the city has no restrictions, if legally binding and properly recorded, covenants can enforce rules that supersede local ordinances for those living within the neighborhood.