Design

No, it does not. For further queries, visit:
www.nid.edu.com

First question how B.com instead of your area of interest will give you business idea? For business idea any graduation can't assure you that but your dreams, likings or could say passion can do so. I would suggest convince them about your dreams and take decision.

If your interests lie in MBA interior designing you should definitely pursue a course in interior designing. Scope in interior designing is immense, and students go on to make lucrative careers after completing their course in interior designing. For now, you should focus more on your course in B.Sc (Home Science), and make plans for the future side by side.

You seem to have already decided the course you wish to pursue and that is fashion designing. You may pursue the same course from either NID or NIFT.

No. See the reason NID doesn't prescribe a syllabus and changes its pattern every year is to discourage this recipe style of reaching solutions.
Doing coaching is like walking on a rope bridge you loose freedom.
Stay original. Keep observing. Sketch everything, for drawings, speak always speak the truth. Watch anime. Keep doodling.