Hi there,
Sorry to hear it did not work out for you last year, but it sounds as though you have a good starting point for knowing what you can improve this time around. It's always important when you re-apply to show what HAS changed since last year, and to put together new essays and anything else you can showcase, and yes applying earlier is recommended! If you are very interested in Columbia and plan to apply ED that can be a plus as it shows just how much you want to go there, which helps.
To your q's:
1. Yes, leadership roles in extracurriculars can still help. And within your job, even if you don't say get a promotion, look for opportunities even if 'smaller' to step in, take the lead on things, initiate something, take ownership of a project or goal, etc.
2. I'm less clear on your question/thought process here.... overall it sounds like you are saying there won't be a difference in your profile/app in R1 vs R2... so are you just figuring it'd be too tough to apply to all R1 so asking how to split them up? I'd apply to those you are most interested in for R1, as that is when they have the most places available. And as mentioned applying ED to Columbia demonstrates your further interest in their program.
Be sure for any school that you really show you KNOW the school well, and make a case for why that school is right for YOU (vs other applicants - make it personal).
If ever interested we do offer a ding analysis for more in-depth review of your applications (
https://www.mbamission.com/services.php?package=ding) , as well as a free 30 min consult,
https://www.mbamission.com/consult.php. Feel free to drop by here with q's as well. Good luck!