Accounting

CS is doubtful but for IT, you may check out last year's cut-off and get an idea.
You may have to wait till the institution rounds.
Also, it depends on the overall result.
Keep checking the college website regularly once the results are out.
The institution rounds go on till the last day of admission.

If you are poor in study, then I am afraid you will not able to do any demanding course. Also, ICWA is not a valid course as far as I can tell. If you are asking about CA course then understand that it requires very hard work.

Yes there is a university level entrance exam there for admission into B.Com accounting and finance. Rest you can call their admissions cell to confirm about the same.

Except CSE, you can get all the branches in the above-mentioned colleges. You can get CSE in the 4th or 5th round.

I would rather suggest you to go for IIT first and do not lose your 1 year in B.Tech. If you don't have the option right now then you should study and prepare for the entrance exam of IIT then if pass then further procedure will start.

Dear,
A student, who has completed +2 with Science having Mathematics as a compulsory subject and has covered it sincerely, can smoothly handle BBA in Maths & Accounts.
Best wishes.

Hi Shubhanshi,
Registrations for the ICAI Foundation & Intermediate courses are open throughout the year. However, students willing to appear for June Term Examination should apply before 31st January of that year and for December Term Examination should apply before 31st July of that year. You can click on this link for a detailed guidance https://www.shiksha.com/accounting-commerce/accounting/exams/icwai-exam.

COMEDK 2018 College Predictor
Use your COMEDK 2018 rank to see where you can get admission a the link provided below:
See the courses, colleges & rounds you may crack
The result is based on admissions data of COMEDK 2017
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https://www.shiksha.com/b-tech/resources/comedk-college-predictor.

Yes, in the first year you need to study accounting as a subject. It is compulsory.