B.Com

A B.Com graduate has a variety of options. Some of the courses that can be pursued are:
1. Journalism
2. Animation
3. Graphic designing
4. Sports & nutrition
5. Cost accountancy
6. Law
7. Performing Arts
8. Expertise on SAP/Oracle/TALLY ERPs
9. M.Com
10. B.Ed
11. Ph.D
This would depend a lot on your interest areas. It has been observed that a person who pursues a career in one's interest areas generally does well for himself.

You should pass all the papers in your B.Com, and then you are eligible to appear for Admission in the LLB (Bachelor of Law) - three years duration course.

Yes, you can apply for B.Com (Hons).

The fee structure is around 3 lakhs.

No, you cannot get direct admission. You have to start from the scratch.

Dear Meet,
Refer to the below link for the best colleges in Nagpur based on ranking. The website also mentions the college fee structure, entrance exam if any and other information regarding the college. The student review also gives an insight about the placement, campus life and course curriculum:
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/bba/colleges/bba-colleges-nagpur&ved=2ahUKEwjqss7fxMPiAhUhmeYKHbqdByAQFjAFegQIBBAB&usg=AOvVaw1eP2-eaHv88zCR-zUOyfXe&cshid=1559229039874

Yes, they accept this board marks for B.Com.

Go for simple B.Com as you are already doing your side work which is more important, else, go for B.Com professional.

No, it's better to take CAT exam only after pursuing your graduation because to get a call from IIM, it's necessary.