I don't completely disagree with you, of course, but if the unjust law is that you get shot in the head for giving someone the finger, and then you proceed to give someone the finger and get shot in the head, you might be a brave hero, but you're still pretty stupid. In this extreme example, there are much better things worth dying for, just as there are much better things to rebel against and go to jail for than laws that prevent you from growing cannibis.
Also I don't think you can make rebelling against unjust laws as a heroic action a universality, even though there are many cases where it is. Though based on the definitions you're putting forward, I don't think someone that is scared of the consequences of what really isn't a very potentially beneficial action is a coward, and I don't think someone growing weed in their backyard for personal use (or selling) is a hero.