CAT

If you have a placement offer in hand , it is not a big issue in not clearing CAT this year. You can work for 2-3 years and then attempt CAT through which you can get into top institute.

Check the Institute for Financial Management and Research (IFMR). It is known for finance and is at par with IIMs. It is among few colleges that provide financial engineering course. It has 100% placement record with good corporate presence. Year by year, placement record is getting better, this year the average package hiked to 8.65L. It has good campus infrastructure and faculty to student ratio is 10:1. It is one of the best college to join for MBA in finance.

Yes, its necessary to give atleast one entrance exam.

50-70 Percentile is general range for OBC and backward classes category of students.

sorry my friend there is not any category system
only marks will be matter approx. 70percent marks atleast you have from 12

You may refer to following link for all details on CAT 2016 examination: https://iimcat.ac.in/per/g01/pub/756/ASM/WebPortal/1/index.html?756@@1@@1

Both have different formats of studying. For CAT, you need to focus on data interpretation, logical reasoning and verbal aptitude with as much as mock exams you can give.
For TOEFL, you need to focus and practice your speaking and hearing skills and need to be well versed with words and synonyms.

Yes, you can apply after the CAT result.The deadline is Jan 31 2017.
Application forms should be out shortly

yes you can. all major b schools in India accept GMAT scores. 650 is a good score. minimum cut off for IIMs is 550 .