Engineering Entrance Exam

If you studied 12th then you can definitely appear for JEE Mains. If you joined Diploma after 10th, then you can't apply for JEE Mains.

It depends on what branch and what rank you get in COMEDK and so on. I suggest, you call the college and talk to them once regarding admission.

What is your category?

Here is a blog comparing CSE and IT. Kindly go through it. Hope this will resolve your query:
https://www.shiksha.com/b-tech/articles/comparison-between-engineering-branches-cse-and-it-blogId-8490

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!

Hello Dear
For agriculture courses, you need to appear the ICAR examination. and after that you'll be pursuing BSc Agriculture.
All the best. Feel free to revert!

You should but it will depend on your rank.

You can try your luck in DTU counselling. IIITs and NITs seem to be tough with this rank but anything is possible. You just need to have patience and wait for all the counselling till spot round. GFTIs are not as much better option as the above two are, so keep that as a back up plan. All the best.