Commerce

Yes, it is good, if you want to study in India and for commerce subject, you may study in Indian school.

Checkout this answer on shiksha
https://ask.shiksha.com

There are various branches which don't have Maths. And, there are some branches, which have Maths in only few semesters.
BCA, Fashion Design -Interior Design -Hotel Management- BA -BMM -B.Sc -B.Com (Pass) -Animation -Multimedia-Graphic Design-Web Design-Game Design-Mass Communication are some of the career options without Maths.
You can choose any of them depending upon your interest.

Hi,
Placements (as provided by college) Companies / Recruiters who visited the campus:
Axis Bank Convergys CSC HDFC Bank ICICI Info Edge (India) Ltd. Infosys Raheja YesBank
https://www.shiksha.com/bba/course/bachelor-of-business-administration-faculty-of-commerce-and-business-studies-manav-rachna-international-university-faridabad-248344

Yes, you can but if you want to become a qualified English teacher, I would suggest a PG in English (2 years). This could get you work as a corporate trainer. A Bachelors in education can help you find jobs in schools, although if you do have a good command over the language, you could simply try your luck without it.

For B.Com, the admissions are mostly on the merit basis. So make sure you get a good percentage in 12th.

Applicants wishing to enter this program should meet the following requirements:
- Twelfth Grade / Intermediate / Standard XIIth / A Level or Equivalent
This program has an IELTS English language proficiency requirement.

From science, you could only switch to arts. There is no option of shifting to commerce.