B.Com

No, MBA program at IIT Kanpur is not open to non- engineering students.
There is also no provision of management quota, applications are selected for GD PI solely on the basis of CAT percentile.

Yes, there is an opportunity for you but if you have anything strong like your academic or any entrance exam percentile then there is an opportunity for you.

You can apply for colleges - Doon Business School, Amrita Business School, Bengal Institute Of Business Studies, PSG-Coimbatore. Check the below link for more colleges-
https://www.shiksha.com/colleges-accepting-cat-scores-range-60-to-70-percentile-article-11984-1
I would suggest you must try one more time for CAT, as you won't be getting any premiere B-School at this score. You can try one more time and score good percentile.

If you want to pursue MBA further then BBA is a better option and if you want to go completely in commerce sector and not in business then go for B.Com. There are many good colleges offering both the courses.

Scholarships are mostly given by universities to students who are academically very strong, have a good profile and/or can demonstrate financial need. You must visit various university websites and check the financial aid section.

There are many courses after completing your B.Com. It depends on your interest that in which field you want to study further. You can choose CA, CS, M.Com or you can do MBA from a good college by cracking the CAT exam.

You should aim for a minimum of 60% in B.Com and 95+ percentile in CAT for a good college. Less than this percentile, you cannot get a good college.