Commerce

You can find the previous year's cutoff details here: http://www.iimrohtak.ac.in/addmission/wat-pi-2015.html .
Yes, there are a fair number of students from commerce background, in fact, I am one myself.

Other than CA and CS, you have ICWA and CMA which are also professional courses. You can do one of them. But you need to have patience and very hardworking.
Or, do an MBA in a reputed college after B.Com.
Or do M.Com after B.Com.

Yes, you can. Acting does not require any particular stream in class 12th. They generally have acting interviews/demo for admission.

Complete an undergraduate degree in a broad field. To qualify for a Ph.D programme, you will need a solid record of undergraduate coursework from a reputable university. This degree should demonstrate your potential for both advanced coursework and independent research.

Gain better marks in economics, so that you can choose BBA.

The minimum age for admission shall be 17 years on 31st December of the year in which admission is sought. Minimum Education: 10+2 class passed with Science (PCB) & English Core/English Elective with aggregate of 45% marks from recognized board under AISSCE/CBSE/ICSE/SSCE/HSCE or other equivalent Board.

Hi,
Yes, you are eligible for the B.Com.
But, as you are science student, you need to work hard initially, because things will be new for you. The laws, concepts, and the formulas etc .You need to focus more on accounts, as the things are totally new for you. Don't worry, you just need to some hard work and everything will be fine for you.

Hi Adarsh,
Prospects are very low. Chances are that you will be accepted by a low ranked university whose degree won't be recognized elsewhere and your investment will go in waste. So be wise and decide. Also visa chances are extremely low. You can try applying and good luck.