Correct me if I'm wrong, but don't they refrain from saying "We HOLD" for dicta? Doesn't that make it a holding and thus case law? If the fifth circuit is asked to rule on the same thing again, wouldn't they again say "individual right?"
Unfortunately there is a lot less integrity to our courts' opinions than meets the eye, and all one has to do is look at the turmoil in Bush v. Gore to know it's true. Switch that outcome, and probably 80 percent of our esteemed jurists and law professors would have found a way to switch their reasoning.
I should give the opinion more attention than I've had time to, but I'm quite confident that any other court looking at this that wants to rule against the Second Amendment, including on the basis of this insane collective right idea (do we have a collective right of free speech? In that case, shut up.)will be able to do so, simply by saying that Emerson's right was restricted in any case, which could have been the result no matter how they decided the collective right issue.
Even so, you may be right, technically. Since the collective right reasoning was decided, it may well be substantively part of the decision, and binding upon any court of integrity. Good luck, there. Your odds probably exceed 50 percent.