As I understand it, Gorman's first counter argument implies determinism in physics. However according to Richar Feynman there is a certain amount of inherent randomness in quantum physics. I haven't studied enough of it to go further and develop but if you watch his lecture on Quantum Electrodynamics he gave in New Zeland (available on YouTube) he'll give you an excellent example of the randomness of the photons that bounce off of glass ; on a macroscopic scale, the photons that make you see your reflection while looking through certain windows.
However I (with my relatively limited knowledge of physics) find the theory to be a sort of reconciliation between the physics we experience and the one of the very small. Really it seems to merge from the instinctive repulsion people have with chance and probability and from a philosopher's mind (distinction: not a scientists). It's not solving a real problem, just a counter intuitive fact with a different (and maybe slightly more pleasing) counter intuitive idea.
It's the same as saying "the photons appear to bounce randomly but it's just because there are even smaller particles that we can't detect for some reason but they have a strict complex pattern that gets in the way of certain photons".
All that being said, I don't understand enough of your last source to tell if it's gibberish or if it gives more pertinent reasons for there to be a different world appearing every time you shine a LED on a pond. And after all, if there is a world where I chose ketchup instead of mustard on my hot dog, the one choosing ketchup is just as much "me" as anything. If multiple worlds start to merge at the beginning of the universe, then every possibility is covered and everything that could exist exists. If there is no beginning point to the growing tree of possibilities, there is an infinite number of other worlds (also covering the infinite number of possibilities). In any case everything exists but we can't interact with anything else. How is that different from there being no other world than ours?
The distinction could be made if interaction between worlds were possible but if it is then (since everything is possible), there would already be an astronomical (or infinite) number of worlds interacting back and forth with our world and in at least one scenario, we would be aware of it.
EDIT: an interesting subject nonetheless