IIIT

I don't think so, in my course there is no any option like this may be others allow .

Yes, in IIIT Manipur easily after participating in CSAB round.

With 83 percentile in JEE Mains, admission to CSE in top NITs or IIITs is unlikely for General category. However, you may get lower GFTIs or North East NITs and CSE-related branches like IT, AI/DS, or ECE in newer IIITs or GFTIs through JoSAA/CSAB rounds.

Options depends upon you category and homestate, so complete your question. 

You JEE MAIN rank is too good . It guarantees you good seat in good college.

For IIT seat it will vary from category.

Appear in JEE main, score good percentile and participate in JOSSA AND CSAB counseling and get admission.

It varies from college to college, but to be honest average package is just a trap . But it still will be from 7-8 LPA .

I am again repeating it varies from college to college.

No, until you are from SC, ST category.

IIIT ALLAHABAD, IIITM GWALIOR, IIIT DELHI and so on .

No , that .5 percent will make barrier in it .

What are you asking .

Even if you were from General category you can get .

But as you are from SC category no one can stop you from getting a good seat in good college with good branch.