Hi DrowsyPirate03,
1. Do you have to go to school right now? I'm not entirely sure from the above but it seems like you might have only about 2.5-3 years of work experience so far. For the most competitive programs on your list, that puts you below the average in work experience as well as GMAT at , and as you say, you are in a very competitive category. So my best suggestion for those programs would be to wait another year, boost your score and work performance and do some volunteer work/community work NOW instead of worrying about the past that you can't change. Then you would be in a much better spot!
If you must go now, you certainly can try at the schools you've named; you indeed might find success at the less selective programs. The admissions process tends to be holistic, so do your best to articulate your strengths and fit with the programs.
2. I would not try to lie or exaggerate about past extracurriculars, but perhaps there are other things in your life, even personal pursuits, that you are overlooking that might create an interesting story here? If not, I'd try to play up what DID occupy your time, school or work-wise. Or perhaps you were working or taking care of family or had a long commute? These things might be helpful context for the ad com, but just try to make sure that it does not sound like you are making excuses but providing useful information in a matter of fact way.
3. To answer your score question, you can look up averages often (not always) via search/ on their web site in class profile pages, but as you say, you want to keep in mind that you are in a very tough category and you might be lower on some other factors too (work experience). Also, for MBB consulting, schools often look for very good GMAT scores because it can play into the recruitment process down the line. So a better score is likely to help your chances! Good luck with your test retake, I am crossing fingers for you!
Warmly,
Julie-Anne Heafey
mbaMission