A very interesting and productive perspective. But as a perspectivist, I have another reading:

Each of the three perceivers describes a different reality. But there is a fourth perspective: that of the narrator of the tale, who tells us that the object is an elephant. (In your post, Uncle Roy's perception is a fourth perception, but it's not necessarily a supra perspective.)

Now most of us don't have access to this fourth or supra-level perspective. But we can approach this reality (notice that I am not at this point in my argument privileging the supra-level--that's another discussion) by comparing notes, replacing subjectivity with intra-subjectivity. We are in general better off pooling our various viewpoints than sticking with just one of them.