B.Com

You can do the B.Ed through distance mode from open universities.
Good luck.

Their admission will depend on both. So, you have to perform well in class 12th as well as in entrance exam. Good luck.

You can do event management after completing B.Com as you cannot do 2 degrees at the same time. So, first, complete your B.Com.

Yes, you can pursue MBA this year and in MBA, your work experience will be counted and also after MBA, your value will be raised. So, I think you can go for MBA.
Good luck.

Narsee Monjee has reservations only for physically disabled. No Jammu & Kashmir, OBC, SC/NT. But other colleges under Mumbai University do have Kashmir migrant quota.

Yes, definitely, you can pursue but at the initial stage you may feel difficult of the subjects like Accountancy, Economics and Quantitative techniques but I hope you will catch the flow. Thus, the answer of the question is Yes you can pursue B.Com after Science.

Eligibility For B.Com in Patna University:
1. Minimum 45% in 12th (This is for commerce student)
2. The candidate who has completed there, graduation in arts or Science the eligibility is 50%. Admission Process :
If you are eligible then you need to appear for the Entrance Test conducted by the Patna University. Admission is based on the marks obtained in Patna university Entrance test.

Some such entrance tests conducted by respective universities for admission into BBA course are:
IPU-CET
SET
AIMA UGAT.

BBA is related to business related studies whereas B.Com is specifically related to commerce related subjects mainly focusing on accounts related subjects.