India

Yes, automobile engineering has great scope in present situation. If have good CGPA in your academics and a decent score in GRE then you can get admission in German universities. Settling in Germany is quite easier than US and Canada.

You are eligible fro GNM only, for B.Sc. you need 12th standard with PCB.

If you want a college in Delhi and do not want to give CAT then you can give either MAT or CMAT. These will give you good options for colleges and also you can try for IP University exam for MBA, it has good colleges in Delhi for pursuing MBA.

There is no value of B.Com from private colleges and on top of that there is no specific college, especially for B.Com. If you get admission in DU, only then there is value to your degree. Otherwise, go for BBA from Amity University, Sharda University or any other top B-school. Same goes for B.Com. If you have hard core interest in the same then go for the same universities.

Yes, of course, it is interest that defines whether it is a good decision or not. If you are interested, there is a lot of scope in hotel management studies across the world. Try the given below link to find the top 10 colleges offering courses in HM:
https://www.shiksha.com/top-10-hotel-management-colleges-in-india-article-10022-1

You should go for Christ University, Bangalore, it is the best institute for the same.

You can do B.Com through correspondence or BBA, I would strongly recommend you to do the same in correspondence if you want to do MBA further.

Please refer to the following link for All India ranking of Medical colleges: https://www.shiksha.com/top-medical-colleges-in-india-rankingpage-100-2-0-0-0. BITS Pilani currently does not offer medical education.