Consider the following premises. There is at least one y for which y will play a game or y is not a musician. For all y, y is a musician if and only if y will play a game. Can we infer the following from them? If we can, name the inference rule being used: For all y, if is not true that y will play a game if and only if y is a musician.
That contradicts the premises. Therefore the answer is no.