Who pays closing, and commissions s in a novation?

[Herminio Tobias]

Hey guys I found a property in Houston that is being sold well under market the house is absolutely beautiful! only problem is it has major foundation issues. I pitched a novation agreement to the seller,where i fund the repare cost, and sell the property for market value. I wanting some feedback on a few things. would i be the one paying the closing costs on the property? or would that be the final buyer who buys the property after me? and another thing how could i secure my self from getting blindsided by the seller and trying t sell out from under me. thank you any inpute yal may have.