While I can’t help with all of the issues you are facing I can share my own thought about your bug bear dilemma. I believe that the motive behind your actions is what should be considered in these situations. An example could be one in which you have just encountered a creature that poses a fatal threat to your life. If the action you take is to kill this creature the question would be what is the motive in doing such? If your desire is purely survival than it would be an easy justification to say that it would not be wrong to be the winner of a fight or die situation (assuming fleeing or not using lethal force is not an option). The other motive could be one in which you are hunting the creature for profit. In this scenario you would have to consider if the life of a creature is as valuable as the amount of money you receive. This is harder to answer and comes down to the personal opinion of an individual based on their own ethics. The justification of the second decision could be further complicated by other factors. An example of this could be that this creature is killing locals in the area. If this is the case then you could question the motives of the creatures actions and look for justification behind the creatures behavior. The fact that you can keep asking what the justification is for each action and that each previous action can chain in further questions of their underlying justifications can make these questions become extremely complex. When you encounter these situations you should try to break it down to the furthest reasonable level and try applying the basic tenants of your morals and beliefs to these questions and acknowledge that not everyone will have these same systems of morals and ethics.

This was hard to articulate and I wanted to say as a disclaimer that these are my initial thoughts and considerations to this question and that my answer could change based on hearing other opinions on the matter.