JEE Main

Yes, you can. Since last year, CBSE has defined the cutoff for PWD category separately. That is 1 mark only. It means, if PWD person will score 1 or above, then the candidate will be eligible to appear for Advanced exam. This year the cutoff is not release since the result is not announced. For more details please check this.
https://www.google.co.in/amp/indianexpress.com/article/education/results-declared-cbse-jee-main-2017-iit-madras-jeemain-nic-in-cbse-see-what-you-need-to-qualify-for-jee-advanced/lite/.

The qualifying cutoff for JEE Main can be somewhere be between 75-78, as per my predictions. All the best for your future.

It depends on your category. It is difficult to get Government College with these marks, if you belong to general category, but you can apply for some private universities too.

Minimum marks are basically called the cutoff marks, which is different for all category. Cutoff is high for the general category. Generally it is nearly 100, last year the cut off was very low comparatively previous years that is 81 for JEE main. For this year I can't tell you since the result is not release yet. It will be going to release on 30th April and the key will be released by 24th April. So, you are going to find your answer when the result will be released.

Yes, then also you can enter into good engineering colleges by giving their Individual Entrance Test. Some examples may be VIT Vellore, SRM Chennai.

Best books to prepare for JEE Mains are:
IIT JER Physics
Problems in Physics.

Yes, you can get any government college of your state. Be aware during the time of counseling. To get more insight about college, you can get please visit Shiksha JEE Mains college predictor app, here is the link-
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor.

Kindly go through the Shiksha JEE Mains college/ rank predictor app to know more insight about your college and rank. I am sharing the link -
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor.

No, your marks are less to get an NIT, but you can get other government college of your state. Stay aware about counseling. You can prefer Shiksha JEE Mains college predictor app to get more insight about college you can get.

If you want to do B.Sc, when you are preparing for JEE, then it is possible. But, when you go for engineering degree, you have to leave B.Sc and need to take TC from the college. This is because, a person can do only one regular degree at a time. If you take admission for B.Sc through distance learning mode, then you can do your Engineering as well as B.Sc degree simultaneously, because a person can do a regular and a distance learning concurrently.