BA (Hons)

Check out the details of B.A. In international relations in Kolkata
https://www.shiksha.com/humanities-social-sciences/colleges/international-relations-colleges-Kolkata.

You can become a web developer, Computer software and hardware engineer, Mobile Application developer, Video game designer, etc.

Not more than 20000.

Yes, you can go for B.A. ( Fine Arts) after your 12th in commerce. Eligibility criteria for taking admission in B.A. ( Fine Arts) in most of the top universities is pass in 10+2.

For 1st year, fees is approx INR 26000
For 2nd year, fees is approx INR 23000
For 3rd year, fees is approx INR 24000

Yes, you can do a Certificate course and B.A. Hons. Together with appropriate time management.

Yes, if you have good marks.

Do apply in the college/University where you want to take the admission.

No, you can't change your time period.

There is no issue you can do in you want to do creative field but it more different from pharma and you should have good drawing skills with you already. You have already completed your B.Pharma you will still be eligible but it may be possible that no credit is given to the Bachelors degree that you have done.