Teacher

Yes, you can get government jobs. As you are from BBA background, you can find better opportunities after MBA. You can try for ETT, if you are interested in teaching.

A graduation degree along with B.Ed is the required educational qualification for TGT jobs and a post graduation degree along with B.Ed is the required educational qualification for PGT jobs.

Kindly visit the link mentioned below:
http://ctet.nic.in/CMS/Public/View.aspx?page=39

You have to clear the NET exam for it. You can then get a JRF.

It is recommended that you do PhD to work as professor in a government college and university. You are advised to clear NET examination.

Yes, it is fine.
Start with B.Ed. program after 12th and then go for M.Ed. or do Bachelor's and Master's in your specialized field.

You can become a teacher by opting either of the modes:B.Com + M.Com + B.Ed from a recognized institutes in India. Apart from this, you need to qualify TET conducted by state or CBSE. B.Com + M.Com + NET/ SET + if required, PhD.in any specialized subjects in finance.Along with that, you can read national newspapers for GS and employment news.

Not recommended, please get a reference letter from 9th and 10th counselors or teachers only, someone who is currently evaluating you and knows your skills well enough. Your 8th grade teacher may send in an additional report.