BFA

If you opt for B.Tech then you will face competition in the society and if complete it, you would have a larger pay scale with direct employment with a reputed firm. On the other hand, there will be less competition and you would do better too with that, but there is less demand for it.
Good luck.

Admission to the course is based on the performance in the relevant admission test conducted by the university which you have applied for. Shortlisting is done on the basis of obtained merit. Preference is given to those who have previously done arts or painting at the HSC level.

The minimum duration of BFA is 4 years. You cannot gain a Bachelor's degree otherwise. If a course is less than 3-4 years it'll be called a Diploma.

Sorry, now changing of the course will not be possible. Doing so will be a waste of a year.
It would be better complete B.Com.

BFA Animation is a 4 year Degree whereas B.Sc/ BA Animation is 3 years. BFA Animation would give you more time to learn. However, 3 years degree can be followed by a 1 year stint in a studio which allows you to be ahead in terms of your career. Please refer to the link provided below for details on its difference in scope and career:
https://ask.shiksha.com/what-is-better-to-pursue-bfa-animation-or-b-sc-animation-qna-2388029

To get a better understanding about the scholarship please refer to the link:
http://www.amity.edu/m/Scholarships.asp
Mostly the scholarships are given based on your percentage in class 10th and 12th.

The best option is to ask the current 1st year students for the same.

There will be an aptitude test where you will be evaluated on the basis of your painting, sculpture and designing skills. Practice drawing and painting, sculpting objects from daily life. You can use scrap objects to create sculptures. Focus on color, light and shadows. In painting experiment by mixing colors to create other colors (ex- mix yellow+red to create orange). Do not use black for shade or darkness.

Yes, you can do that as University Grants Commission has given a go ahead to students to pursue two-degree programmes simultaneously.