BBA

One of the possible option is Avalon Academy, Patna.

University migration may not be possible. It depends on your university rules and regulations whether they can give migration and also on the university in which you want to take admission. College migration is possible within same university. University migration is provided only in special cases b

Most fo the colleges require at least 50% marks in 12th standard.

Manav Rachna is s good university with good placement records. They have a huge campus and good learning and study environment. Their faculty is also good. You can read the reviews through below link.
https://www.shiksha.com/mba/resources/college-reviews

IBPS bank PO is based on mental and logical reasoning test. The syllabus of IBPS PO exam consists of logical reasoning, general awareness, language ability test, quantitative analysis and data interpretation. There are no questions related to any specific subject. But pursuing BBA will help you to a

It depends that on in which college or university you are pursuing your BBA from.

https://www.shiksha.com/bba/colleges/bba-colleges-pune
Go to above link to get a list of BBA colleges in Pune.

Dear,
It is a good and useful idea provided you are giving your best and sincerest effort to reach your goal. One thing I would like to add is if possible take the assistance of professional coaching centres if required.
Best wishes.