I have how Marcus follows the theories of ethical subjectivism because of pushing to make a sacrifice of the 300 people on the Ark to help sustain the Ark a little longer. I also have Bellamy and Abigal for ethical subjectivism because of Bellamy making or persuading people to take their wristbands off and endangering others to protect himself, and Abigal for broadcasting to the people of the ark about how it's failing. Then I have examples of utilitarianism because of sending the 100 and sacrificing the 300 on the ark to help keep the ark running longer. Then Chancellor Jaha as an example of somebody who follows Deontology Duty-based ethics. I am trying to look for other theories that could be found.
I doubt that I can be of much help, but if no one else will pitch in. Take note that the official theme of the season is "Survival isn't who you are. It's who you become." And that the show often use parallels to contrast various issues among the Arkers, the Delinquents and the Grounders. You can often identify a pair with idealist/cynic view on each topic ( Jake/Council, Abby/Kane, Clarke/Bellamy, Bellamy/Finn, Clarke/Anya, etc) from there its really about what issue you want to highlight..