Analyst

Moelis Chicago pulls the vast majority of full-times from its intern program. Laterals are very rare. I had a relationship with an MD who essentially made me the offer. I had ~5 1 on 1 interviews with associates, VPs and a couple MDs in the office. Almost every interview was similar in that the interviewer would ask what my experience was and then grill me on the details of that experience. So it seems that they do not focus so much on a set of technical questions, but rather that you are able to learn this kind of environment.
In general, however, Moelis interviews are focused knowledge/learning ability, as well as fit. Core recruiting is straight-forward, typical OCR kind of stuff. Nothing special there. In order to get into the non-core recruiting process you have to know someone, otherwise no dice.
In terms of advice, I would say that without a doubt the most important thing is to know your resume/experience inside and out. An instant ding is when someone has something on their resume that they can't clearly explain. After that it is just being yourself. Chicago office has doubled in size over the past few years and it is doing everything in its power to maintain the culture that it currently has. No way to prep for this, just important to relax and not be too robotic