MCA

Yes, you can opt for higher studies (MS) after completing BCA / MCA in India.

Well, it's having the same value for both of the courses. But these days due to growing IT industries, it's better to choose for B.Tech+M.Tech. It's because nowadays companies serve better package in the technical field rather than in software departments. I hope this was helpful to you.

It depends upon the college you are choosing to study. Normally it comes in between 6L-8L package which includes your total fees of 4 years as well as your other college expenses like security deposit and other formalities.

Depends in which field you want to make your career in. If it is your ultimate goal then BCA+MCA will be a good choice and if you want to go in the agriculture field, then Masters in agriculture after B.Sc. agriculture will be a good.

There is no specific guide for OJEE(MCA). This exam carries 4 general part (English math reasoning and verbal ~non verbal abilities). You can be successful as per your level best.
Good luck.

Merit and management quota basis.

Osmania University Tarnaka, Hyderabad
University of Hyderabad Gachibowli, Hyderabad
Jawaharlal Nehru Technological University Hyderabad

B.Tech is more attractive to employers that a BCA. Before you will do your MCA, your B.Tech will be completed and thereafter, a job cannot be claimed.

No, you can't get into Bharti Vidyapeeth College through GGSIPU-CET exam. You need to qualify B-CAT exam for the same.

Of course, you can, for details check out the link below:
https://www.shiksha.com/it-software/course/masters-in-computer-applications-mca-vivekananda-institute-of-professional-studies-pitampura-delhi-175274