IIIT

You won't get any NITs. You can get colleges of your state, maybe even government ones. Try JEE college predictor to get more information and insight about college which you can get on the basis of your rank-
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=4067795.

No. The order goes like this:
IIT
IIIT
NIT
GFTIs
So, IIIT is better than NIT. But, I suggest you to not choose according to this because it may differ from few respects. So, choose when you are satisfied. Also, if you are getting NIT, then enroll for it whether it is very far away from your home or it is a new NIT.
Best of luck.

You might come across certain difficulties in dropping 2 years as with your age you won't be able to apply to some colleges. You should consider you age as a factor first and if you think you can do well by dropping twice you should go ahead with your plan.
good luck.

It will depend on Category. For General, there will be less marks for NIT.

With this score, you can't get any IIIT for CSE. You can try for lower branches in IIIT.

For IIT u will have to give JEE Advance and on the basis of JEE main u can get NIT and other gov or private college.

It depends on your rank, and the result will only be sure after counselling. As you said about the score, there is a chance that you may get a college. But, not so sure about it. So, wait for the result, and if you have any other exam, do your best.

You will get the good package no doubt. But, if you put some extra effort and make your under graduation very good and also you have extra knowledge about the field, then you may get the high packages. The placement doesn't depend only on college. It also depends more on your performance in interview as well as written test.

Hi Gaurav,
Hope you are doing well. There is no special eligibility criteria for IIIT's. It will be decided purely by your JEE Main score. IIT's are very good colleges, because they come under INI's (Institutes of national importance). If you are not getting a seat in IIT go for NIT after that select IIT. Moreover, it also depends on the branch you wish to select. Some IIIT's are better in specific branches in comparison to NIT's.

If you belong to general category, then you cannot be eligible for any of the NIT with that marks.