JEE Main

Yes, you can get a seat. You are eligible for merit seats in private institutions.

How can one answer this question? No one can answer this question. Data is not given like that. You can only know the last year's cut-off, percentage qualified in each state, general rank or category rank. This type of data is not given by JEE or CBSE. So, don't believe if anyone answers this question. Cut-off will be near to the last year for your home state.

Super 30 is a coaching institute providing coaching for engineering aspirants from the backward category. I cannot find anything like class 10th material on its website.

At least 35K rank is needed to get lower branches, 20K to get core branches and below 10K, you can think of getting CSE. So, target for under 20K to get a good NIT.

No (as per the last year's statistics). But many seats were left empty last year, so you may try to get a seat if you're lucky enough.

As you know, every student works hard but toppers have a different strategy of smart study which differentiates them from the crowd. The secret of getting more than 250 marks is focusing on those topics which are not asked or very less often asked in the paper. Secondly, revision of topics and paper solving
Thirdly, giving mocks. Do these things and surely success will be yours.
All the best.

It's hard to get admission in JK Institute of Applied Physics with such a rank. CSE branch closes at around 7000.

Hello,
Well, you can use college predictors. One of the predictor's link is given below:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
And also check the official website for opening and closing rank in the last round (round 7) for 2017 to know about your preferred colleges.
Here's the link:
https://josaa.nic.in/Result/result/OpeningClosingRank.aspx
And in 2016 over here:
https://josaa.nic.in/Result2016/result/OpeningClosingRank.aspx

Yes, you are eligible for JEE Mains provided you have 75% in class 12th. It doesn't matter that you have appeared for any other examination or not.

Follow the following links:
https://www.shiksha.com/b-tech/course/b-tech-in-civil-engineering-national-institute-of-technology-surathkal-Bangalore-61474
https://www.shiksha.com/b-tech/course/b-tech-in-mechanical-engineering-national-institute-of-technology-surathkal-Bangalore-61468
https://www.shiksha.com/b-tech/course/b-tech-in-electronics-and-communication-engineering-national-institute-of-technology-surathkal-Bangalore-61501
https://www.shiksha.com/b-tech/course/b-tech-in-chemical-engineering-national-institute-of-technology-surathkal-Bangalore-61489