A: A prenup would be binding in a divorce action provided that the prenuptial agreement was written properly, both parties disclosed all relevant financial information along with an acknowledgement that they had the right to consult an attorney of their own choosing before signing, and the signing was witnessed by a notary.
A: Yes a prenup can be modified after it has been signed. Generally speaking, standard prenuptial agreements have a clause that allows for a prenup to be modified provided it is done by via writing and duly notarized and executed by the parties.