Most if not all propositions can be read in different ways, and can be negatived in different ways.

The flaw in your negative statement, Daylia, is that you've given a broader negative than is called for. The correct negative or opposite would be that "Music is not everything."

And of course I have to point out that your statement that
First, if A is true, then the opposite of A cannot also be true is not true in all philosophical systems. Indeed, the very concept of "the opposite" is not always meaningful. Merely inserting a negative in positive statement doesn't establish that the positive statement is a yes/no truth.

Schrodinger's cat is NOT "either in the box or not in the box".

Dave Oesterreich