Nancy will be disqualified under Dan's will. The issue is whether an interested witness may qualify as a beneficiary under the will. A beneficiary under will that is present when the will is executed will properly take under the will provided there are two disinterested witnesses. Ed is a beneficiary under Dan's will. He will be permitted to take under the will because Art and Nancy were the witnesses.
Art is a proper witness.
Attorneys may serve as witnesses. Nancy, however, will not take under Dan's will. Nancy is an interested witness. Therefore, she is disqualified as a beneficiary. Furthermore, she may not even sue Art, Dan's attorney, for his malpractice which resulted in her being disqualified because an attorney owes a duty of care only to his client.