I was about to ask something similar. My question is if you can attack twice, which it seems that you could. But then you find the stats for the Allosaurus, for instance, and their special ability is that they can perform two attacks. So it looks like 2 attacks is not the norm.
As for your questions, I understand that Blocking is not an action as it is declared before rolling for Defending. I would say that Defending is also not an action as it would be too detrimental for the player. And, mechanically, if you don't Defend, you don't roll and you don't get damage.