Hi, I am a current student at cmc so I can answer most of those questions from my perspective.
About 1/3 of students are athletes, but that is only one facet of their experience. Athletes are still students first and are not idolized the way they would be at a large state school. Athletes are often friends with both varsity athletes and non-athletes. There are usually people at games, but the only game that I would say a large portion of the student body attends is the football game against PP. Otherwise it is mostly just a small number of students.
Drinking culture is definitely a part of CMC, however the type of drinking really depends on the students. It is not uncommon for people to have a wine night and focus on conversations or friends having a couple of beers and hanging out. There are definitely some parties for which students do get drunk, and alcohol is part of the party. That being said, I have never heard of anyone being pressured to drink. In fact I have a number of friends who do not drink at all and still have a good social life. The drinking culture is really what you make of it. If you want to go get drunk there is a place for that but if you decide that you don’t want to make that a part of your cmc experience, nobody will ever force anyone to drink.
The political leanings of the school is well balanced. There are more conservative students and professors at cmc than at the other 5C’s however there are also a good number of very liberal students and everywhere in between. What most of us value is the ability to have a dialogue with people who have a different opinion than us. Cmc student range from very liberal to very conservative and everywhere in between. There are also some students who are not interested in politics. As for professors, there is a good mix of conservative and liberal professors. They are almost always open to opinions that differ from their own. Very liberal students who express their views can do very well in class with more conservative profs. I have also had a number of gov profs where I still have no idea which way they lean.
As for do students regularly have communication with their professors outside of class, the simple answer is yes. I have developed great relationships with a number of my professors outside of class.
For your question on debate, I have absolutely no idea, sorry. I know most of my friends who did debate in hs usually try out for the MUN and Mock Trial teams, but I know very little about any debate team.