IANAL, but I spent a lot of time on the meetings with lawyers, including securities lawyers (but not related to cryptocoins).
Only the developers truly have the influence to alter the protocol and have it widely adopted. So in my mind the test is whether the developers are acting like an organized controlling manager of the coin.
A) under common law systems:
Your idea of "managerial control" is way to narrow. You've completely neglected the promotion and sales of securities and "managerial control" of said sales and promotion.
Therefore most of your analysis in invalid. One could probably come up with a case where the "security" itself is valid, but was promoted and sold in an invalid way.
B) under civil law systems:
The story is completely different. Under those systems the securities law tends to root in the Roman law concept of "depositum irregulare".
One more thing you seem to be neglecting is that the current prevailing common law definition of "conspiracy" doesn't require a proof of communication between the distributed co-conspirators. It is sufficient for prosecution to show that all "conspirators" acted in furtherance of their common goal.