Computer Science and Engineering

I think you should get around 75-80 GATE score in order to get your desired seat in the desired college which is IIT Kharagpur for CSE. So, you have to work hard. Good luck!

If you want to stand as a professional software engineer then select CSE but if you are expecting a govt. job or if you want to get double degree, then select ECE.

There is not much difference between the fee structure as the difference is very slight i.e. of 10k.
Highest will be CSE.
But from career perspective, there is a lot of difference in jobs, placements, etc.
Thanks.

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

As BCA has less scope, so you better choose B.Tech. But for B.Tech, you need to score 75% in +12th with maths to appear JEE Mains exam.

If you want to further study with your job, then you can choose distance mode course for further course. There are many institutes which provide distance learning in your field.