Colleges in Gujarat

Every semester your subjects are going to change so 27 subjects in total for the first two years overall and then you have to choose one subject as your major and one as your minor.

You need to apply through CAT. The fees for 2017-2019 batch was Rs 21 lakhs for 2 years.

College change or university change is only possible after first year (not in 4th semester) and that is also dependent on the college and university. Some universities allow it and some won't plus you need to have good scores in first year to apply for the same. For further details, contact the college authorities.

See if you are really serious about your career in management then I would suggest you to focus on your study and not on job right now. As when you involved in job then it will be little tough to change to your study and you may face some gap year for regular college. I would recommend you to go for CAT and also there are some good colleges which you must see to get what you need. Visit MICA at Ahmedabad - https://www.mica.ac.in/ website through the link provided and get to know about the college.

To get admission in Ahmedabad, I would suggest you to go for MICA which is one of the top college to fulfill your requirement. It may not be on the 2nd number but will meet your expectations. I am listing the college link to get better idea of the college and the courses offered.
Link: https://www.mica.ac.in/.

85-90 percentile would be enough for a call I guess.

It depends a lot on your complete profile, your academic background etc. Its difficult to annotate a number without any information about you.