I am afraid I cannot take your rationalisations seriously. Arguments about unicorns in bowler hats etc have nothing to to do with your subjective experience of the world. They are merely thoughts in your mind. Metaphysical idealism takes subjective experience of a thing to be the thing itself. It conflates subjective experience and objective existence. This is a fundamental error in my view. If you want to believe that the world only exists as experience, fine. For myself I accept that the world and others exist independent of my experience of them.