IIM Bangalore - Indian Institute of Management

CAT is an aptitude exam, and requires that you are able to apply your mind to solve the questions. It is not hard because of the exam itself (which I feel is way easier than all the Engineering and Medical Entrance examinations) rather it is because of the competition. Hence, you will need to put in as much effort as you can to be ahead of others to get a seat in the IIMs
I believe enrolling into a correspondence process will help you kickstart and plan your preparations well. But that is just my opinion. A quick google search will throw a lot more ideas and plans, that you can look at and follow.

IIM, Bangalore offers a General Management Programme, and gives you ample opportunity to find out, which stream excites you. (Through summer internship and courses) Therefore, based on this, you can decide to pursue the field that you like. As such, there is no one to answer your question as all fields are equivalently great and you have a chance to end up at a CXO position by following any of these.

Check out the official stats but on an average you can expect a CTC of >20 Lakh per annum, for some jobs in finance it can be as high as 70-80 Lakhs, while if you choose to start up on your own or take a not so typical route, it might be a bit less in the starting.

IIM-A and IIM-B offer only general MBA, there is no specialisation although you can take electives in particular field to augment your knowledge of that.
The fee structure of PGDM (i.e. MBA) is generally 20-25 lakh rupees (changes every year).

You have a decent profile and especially you have a great chance at C & L as they put relatively less weightage on your graduation score.

Depends on your year's admission criteria (check the past statistics, a quick google search will throw up the result). But, I believe you should focus on CAT and think about this once you have crossed that hurdle. All the best.

IIM's I would say aren't the end of the world and you can very well reach similar or greater heights in your career despite the IIM tag. You can look at other Indian MBA B - Schools or Foreign B-Schools, that don't give as much weightage to 10th and 12th percentage like ISB.
Also, I would say it is important that you introspect a bit about your career and look for ways to progress where your past profile would not be a hurdle.

There is no minimum score as such (B has >80% criteria, might have changed so do check)
Put in your best effort for CAT, all this comes later, and you anyway can't change your scores.

Yes, but you need to perform well in GD-PI too.

Depends on your CAT percentile and college. Check the point criteria for individual IIM's. Highest weightage is given to CAT.