B.Tech Computer Science and Engineering

There's no minimum percentage like thing in college for placement. Different companies set different eligibility criteria. You should focus on getting 75%+ that will be more than enough.

I would suggest the integrated 5 year degree in VIT because firstly it will save you the trouble of again preparing for GATE exam for doing an B.Tech degree in case you feel interested in your field of study.
Secondly, by doing the integrated degree, you are saving one year time which could utilized

No, computer science and engineering branch is better than aeronautics because, CSE branch is best for Bright Future and good salary for placement in India as well as abroad.
You may go to www.anandice.ac.in/admissions for more information.

I think you should go and visit ICFAI University. Don't go just by the name. There are too many good colleges in Rajasthan, especially in Jaipur which are trying to compete with VIT Vellore, MNIT and LMNIT in terms of modern educational concepts, association with renowned universities in UK, USA, Ca

No, you have to go through the paper of COMEDK for getting admission in the top colleges in Bangalore. You don't need JEE Mains for the same. Bangalore is the best option for doing CSE through colleges like RVCE, MSRIT, etc.

I think you should go with ece branch.Because for upcoming years ece have better scope in our country. Due to changed scenario in world the IT sector is suffering fall. While scope of ece is very wide and have great scope to rise in our country. So you should go with ece.