Best Way to Buy Parents' 2nd Home

[Ty Woods]

We are going to buy my in law's 2nd home in FL.  They owe about $140K on their mortgage.  They are selling it for $280K.  Comps in the area are around $300-325K.  They are giving us a discount since no realtor will be involved. 

We plan on doing the traditional 20% down, 30 year fixed mortgage through a bank.  Are there other options to consider or explore to minimize costs for both parties on all fronts including taxes?

Maybe refinance and add my wife to the deed.  But then we would need to pay them the $140K they have in equity.  

Seller financing?