JEE Main Scores

No, CSE at NIT JSR is not possible. You may get other branches for sure. Don't just rush for CSE. Make a wise decision and if u even get IT ECE and if it interests you, go for it. Those are good branches too. Hope it helps.

You can almost all the branches in almost all the colleges but not the top NITs like Trichy and Warangal. Other than these, you can get almost all the NITs till the last round or in the spot round.

Yes, you can easily get the college without any problem. Even, you can get into almost all the colleges of the Maharashtra but it would be difficult for you to get the desired branch into the top colleges through counselling, there is internal sliding into the college if the seats are vacant in the other branches.

It would be difficult for you to get into the NITs but yes, you can get some of the GFTIs into which you can easily get into the and they also like the NITs and some of the GFTIs is more valuable then low ranked NITs.

It would be difficult for you to get into the top NIT as you quiet low for that but you can get some of the low ranked NITs, I'll prefer you to opt for the GFTIs where you can get some of the top GFTIs that are better than going to some low ranked NITs.

You can only get some of the GFTIs at this rank and not the NITs as you rank is quiet low to get into the NITs.

Colleges have seats for Management Quota also, so you can visit colleges of your interest for discussion, but highly reputed college might not give admission. But, if your ward is serious about doing B.Tech in CSE, then it is not necessary to study in highly reputed college.

The link here of UEM Kolkata will help out with your choices and also gives proper information for admission https://www.shiksha.com/university/university-of-engineering-and-management-kolkata-47398/admission.

Admissions in IITs are done on the basis of rank scored in JEE ADVANCED exam.
So, one has to first qualify JEE MAIN exam and then score a good rank in JEE ADVANCED in order to get admission in IIT.
Best of luck.

DTU is a better option than MNNT, Allahabad.