NIT

Yes, surely you will get.

You can get VNIT but not NIT-Rourkela as getting there is quite difficult, according to last year admission score.

As per NIT Silchar placement cell officials, the average annual package offered to students is Rs. 4 LPA and the highest annual package is Rs. 9.5 LPA during the campus placement.
Coming to teaching methodology there is a pre-decided course structure assigned to each of the departments, it depends upon the teacher who takes up that particular subject, some teachers are good at explaining the concepts while some moderate in such cases we always have video tutorials to our rescue which helps us to pass the exams.

Here I suggest you a site for your question
https://www.quora.com/Are-there-any-IIT-institutes-for-astronomy-astrophysics.

It totally depend on JOSAA counselling. You may get NIT-Allahabad, but IIIT-Hyderabad is best. IIIT is among all the IIITs, so you cannot get it.

You need to score 60% marks to get into an NIT or IIIT. And if you are looking for IIT, then you need to have 75% marks in 12th class. Hope this helps.
Thank you.

Well, you can't clear JEE Main with your board exams. You have to study really hard for JEE Main, and as you said you want NIT, so try hard to get 150+ marks in JEE Main exam to get NIT and in board exam 80+ percentile as a save zone.

According to my knowledge, I would say in boards you must go for 75+ percentile, as it also work for scholarship and in JEE Main 140+. And, yes it all depend on the cutoff of every year and the field you are going to choose. I hope it help you.

First of all, congratulations for your rank. Yes, of course, you can get seat in NIT or GFITs. Keep trying.

No, NITs don't have any such team as they only check the PWD Certificate of the candidate.