IIM

An UG degree is essential for applying to IIMs for a management degree. If B. Com is the only UG degree you have then it will be considered essential for the admission. So yes, your percentage in B.Com will be a part of the evaluation and it will carry a certain weightage in overall evaluation as well.

MANAGE-Hyderabad is ranked higher among the two. The faculty-student ratio is higher for MANAGE among the two. Fee is almost same for both the institutes. You can compare the two on other factors, below are the links-
https://www.shiksha.com/mba/course/post-graduate-diploma-agriculture-business-management-national-institute-agricultural-marketing/24472
https://www.shiksha.com/mba/course/pgdm-agri-business-management-national-institute-agricultural-extension-management-manage/7234

Yes, you will be eligible. But, the chances are less. Most top IIMs look for students who have performed well consistently. However, if you perform extremely well in CAT then the chances of getting interview call are higher.

In view you have got call from IIMs, you stand high probability to clear it this time. Admission to IIMs happens on the basis of multiple parameters, therefore, you must try to do your best in the GDPI. All the best!

For admission in IIMs there are several things which can be considered:
1. Entrance scores
2. Past academics
3. Extra-curricular
4. Social participation
5. GD/PI
After considering your performance in everything they allocate seats.
So, score good percentile in CAT and get yourself a call, rest will come in role after that.

No, for MBA you should be a graduate. Diploma is not a graduation course.

Yes, the CGPA is enough to qualify. You can make to most of the IIMs with this CGPA if you have good scores in CAT/12/10. Focus on maximizing your score in CAT and you are good to go.

It's not compulsory at all. Being a CA gives you advantage in the area of finance as are already aware but it need not hinder you from exploring other areas of management Science. You are completely free to pursue any field and the fact that you are a CA will not be seen negatively. I know many students who pursued Human Resource Management after doing CA and landing great jobs during campus placements. So, the answer is - Study whatever you want, being a CA does not limit you.

Work experience is seen as a positive for any MBA program in general. You are advised to prepare well on your work experience and learnings and use it to your advantage during interviews. JEE in public sector is a good experience. So, be confident when you describe it to interviewers.

Currently, no IIMs offer BBA degree course. IIM, Indore is the only IIM which offers 5-year integrated programme in management with IPM.