The overall percentile required for the ST category in the colleges you listed are as follows:

IIM A - 60 percentile

IIM B - 65 percentile

IIM C - 65 percentile

IIM K - 55 percentile

IIM L - 65 percentile

IIM I - 50 percentile

Looking at the cutoffs you can safely expect calls from these colleges. However, I would request you to go to the respective websites and see the percentage of CAT marks and other criteria since it is different for every college.

The background does not make a difference and in fact, it is better if a person is from a diverse background. Colleges like to boast of the mix of students from various profiles and you would fit in with that really well. Most colleges end up having mostly engineering students as applicants. So, MBA colleges are more than open to candidates from any other background.

Just make sure that you are well versed with the subjects you have studied in your undergraduation. They might be interested in asking you since your background is unique and they will be inquisitive about that.

I suggest you start preparing for your interviews and focus all your energy on acing the best college you can get!

All the best!