CA

Why you want to give up CA? CA is the best option for a commerce student. It is a professional course, so it is quite difficult to clear it at first attempt. If you are interested in doing CA, you should go for it. It will give you a bright career.
All the best.

Yes, you can get experience of how a CA works and how to manage work.

If you complete your MBA from IIM, then you'll earn approximately 2 times then a CA.

You should try to complete your CA.

CA is sufficient for you. It covers a wide area.

Yes, you are eligible for a government job after completing CA.

You need to clear your class 12th to pursue CA.

Yes, students without mathematics can pursue B.Com from DU. It is B.Com honors, where there is restriction on without mathematics student to take admission in DU.

CA itself is the best professional course.
You should pursue B.com and M.Com. I think any other courses are not required.
All the best for your future.

MBA entrance exam is in itself a demanding preparation. In my opinion, it would be better to give your best shot to clear the entrance rather than going for CA article ship. This is because if your exam gets cleared and you are able to seek admission in one of the IIMs, then sky is the limit as far as your career is concerned. Thus, focus on one course at a time. You will definitely succeed.