CAT

For LL.B., I think you meant CLAT results. The results have already been declared on 31st May. Please check for details:
https://www.shiksha.com/law/exams/clat/results

We at Cygnus Educate believe that education should not burn a hole in your pocket. At Cygnus, you would get the best trainers for CAT at a very reasonable fee (less than Rs. 40,000 for any duration programme).

Hello pranay
I will suggest you to go for Bengal instite of management studiesand
bhowanipur collage I find these to be good
All the best for your future.

Minimum qualification required for MBA is graduation or equivalent degree. There are many institutes which provide MBA as well as PGDM courses, if you want to GET it from a top notch institute you need to have good scores in competitive exams too. As you are in 12th take your time, try to know more about competitive exams and institutes providing same courses. Fix your budget and then try to shortlist some colleges or take help of Shiksha. Com
At present IIM Ahmedabad and Bangalore are considered best for PGDM.

Yes, IBS does accept CAT score.

TISS conducts its own entrance test TISSNET. To secure admission in TISS, you need to appear and clear TISSNET.

If you are working, or is in the final year of graduation and is ready to give CAT next year, then surely that's the best option. You can attempt other entrances like XAT CMAT NMAT etc. And try to GET into a good college. But, do make sure you do something productive or take some new courses to add to your CV while dropping the year, because during interviews you might have to justify the year gap. Otherwise, if you don't have any high expectations on the placement side then you can right away take admission in colleges like NDIM, Jaipuria Institute, SCMS Cochin, Alliance Bangalore, ITM Navi Mumbai etc.

No, I don't think so, that there is any CGPA criteria.

Better than just selecting only one college, I would like to suggest you appear for CAT, MAT and CMAT. This will open the doors of many other good institutes for you.