GMAT

There are some universities overseas, which don't insist on IELTS and allot admission only on GMAT scores. However, it is better to appear for both the exams and have a video option.

650 is for the current year, it may change depending on the quality of students and the trends in the corresponding year.

For all the entrance exams, you need to study for more than three hours and need to fix your time for that.
First, you need to have a good grasp on the basics. After that, solve the question papers.

For all entrance exam, you need to study for more than three hours, and need to fix your time for that.
First, you need to know what is syllabus and need to know all basic and after finishing your basic study start solving all the question related to that.

Hello,
Yes, SP Jain School of Global Management, apart from GMAT and CAT, also accepts the scores of its internal assessment exam named SP JAT for its MBA program.
Good luck.

Hello,
Yes, a separate preparation is required for both CAT and GMAT since the level of questions asked in these exams are different from each other. For example, the level of English in CAT is comparatively lower than that of the GMAT. Giving free mocks without any preparation would let you know it in a much better way.

Hello,
To get admission in any good MBA/PGDM college, one has to appear for the required entrance exam (s) and perform well in the interviews (if shortlisted for them). https://www.shiksha.com/mba/articles/20-mba-entrance-exams-you-can-take-this-year-blogId-11473
https://www.shiksha.com/mba/ranking/top-mba-colleges-in-india/2-2-0-0-0
Visit these links for more details.

Typically, 3-4 months with full dedication and devotion is enough to get good scores in GMAT.

Yes, if you have a very good score, then they might give you a scholarship but not 100%.