What should I highlight in my Business Analyst interview at McKinsey?

For the most junior positions (such as business analyst that 20 years ago was for undergrads directly out of school) they will be looking 50% to i), 25% to ii) and 25% to iii). However, you can not be genius in i) and have a lousy score on either of the other two. A junior position is about doing (so hard skills are a must), but they need to see career progression possibilities. So a person that comes across as not able to communicate in a structured way, or without cultural fit will be discarded. Typical pitfall of an engineer: trying to show off coming up with a very complicated solution for the case interview with endless loops. Mckinsey is looking for the opposite: the beautiful simplicity of concepts boiled down to two-three key insights.

Leadership, ability to drive impact, take initiative, work well in teams and solve conflict, come up with innovative ideas, passion for an industry and/or consulting itself. Also don't forget to show case your interests and personality. I hit it off with a partner by talking about the time I did the "Krispy Kreme challenge" and when I dabbled in competitive eating.