You're saying that you're not arguing about semantics, but that's the entire content of your argument. The talk of "practitioners of civil disobedience" taints any arguments that follow. I could just as easily say "other practitioners of yoga feel that actions needed to be guided by energy to be considered justified", and say that Snowden's actions are unjusitifed for that reason (hearty apologies to any yogis out there).
So strip the labels entirely before applying them ruthlessly.
That said, let me talk to the heart of your argument, which is more about whether his actions are justified, rather than what they are called. I would say that Snowden's goals are twofold, in my mind. One goal is to expose a secretive and possibly illegal operation perpetrated by a government that is supposed to represent the will of its people, that was being kept secret despite the fact that publicly acknowledging it arguably does not compromise it as a means of stopping the organizations that it is purportedly targeting, and thus the secrecy was not essential to the operation, but rather was to keep people ignorant of the violation of their privacy.
The second goals is to encourage other people to come forward with information that they feel satisfies these criteria.
The third goal, which is really, in my mind, a non-goal, is to expose the government's harsh treatment of people who reveal government secrets.
Facing trial and potentially being incarcerated furthers only the third of these goals, which is not really even a goal. It hurts the second goal significantly. And it is largely irrelevant to the first goal, which is accomplished whether or not he is penalized. Successfully fleeing prosecution advances the second goal significantly, and only hurts the third goal. I don't see how the fleeing prosecution affects the first goal in either direction, which is the most important one.
So are his actions justified? I think, as do many others on this site, that the first two goals here are very important ones, and the third is not important, so in my opinion, yes, justified. I hope his conscience is clear. The other question, whether they are effective, is separate, and remains to be seen. I am not optimistic; violations of privacy cause no real substantial harm until they do, and at that point it is too late to protest. I haven't even switched away from google, and my parents don't even know who Edward Snowden is.