CBSE 10th

For that you can go to your the nearest block. They will give you the solution.

Yes, you are eligible to get admission. Candidates who scored above 80% are eligible to get admission.

Yes you can expect a call from IIM Ahmedabad because your percentile is too good so I am assuring that you will get at a call with from IIM Ahembdad. Your cat score is excellent but you have to pass the personal interview also to have admission in IIM ahembdad.

Yes, you can enroll in B.A. And you will get admitted to second year directly if you are holding a Diploma in Polytechnic.

You must have to clear CAT entrance exam with good percentile first.

No, onlyafter class 12th you can pursue this course and M.A. English is an post graduate course you would to do B.A. In English to do so prior to this.

Yes, you can get and you will definitely get the college.

Yes, of course, you can appear in UPSC civil services exam, the only condition is-:
Candidate must hold a Graduate Degree from a recognised University. UPSC Civil Services Exam Age Limit: Candidate must be a minimum of 21 years of age and must not be more than 32 years of age.
General Category
No matter you had compartment in 10th or 12th but make sure you clear your compartment and have graduate from any stream and your degree recognised by UGC
You are eligible for UPSC Exam or any other Government job
I hope this will help you.

No the marks of class 12th is considerable. 60% in the CAT exam.