IIT Eligibility

Yes, you are eligible to join IIT but for that, you have to appear for B.Tech lateral entry exam and in that, you have to do really good to get an IIT.

For M.Sc, there is something called JAM exam.
You can get more information here:
http://jam.iitm.ac.in/jam2016/ac
The candidates who qualify JAM 2016 shall have to fulfil the following eligibility requirement (ER) for admissions in IISc and IITs. All candidates admitted through JAM should have a Bachel

No, you cannot appear for IIT after this much time. You need to do some other course.

No, there is no such quota in IIT but there is a quota called DASA in NIT and IIIT.

There is no firm and fast degree requirement for security analysts. Nevertheless, most employers are going to be looking for a Bachelor's degree in Computer Science, Cyber Security or a related field. So, you see that through JEE Mains, you get a college and take CS or IT branch which introduces you

Yes, you are eligible to appear for JEE Mains & Advanced and hence for NITs and IITs, Follow the link below for details :
https://www.shiksha.com/b-tech/exams/jee-mains
https://www.shiksha.com/b-tech/exams/jee-advanced

It will be displayed on the JEE Advanced website jeeadv. AC. In. You will get all information from there.

There is no choice in the number of subjects. You have to compulsorily appear in all improvement exams. Work hard and good luck!

For top branches in top IITs, it should be under 500. For low branches in top IITs, it should be under 4000. For any branch in any IIT, it should be 10000 around.

You can surely get good colleges through your ST rank.