CBSE 12th

No, you have to give JEE Mains to qualify for NITs.

Yes, you can apply for this college but for admission in this college. You have good academics record.

You are eligible for this college. You have at least 60% for eligiblity.

You have to appear for the counselling. If you are shortlisted, you have to go college for documents verification.

Sure. You are eligible for this course. Please apply for this.

Yes, you are eligible. Check the cut off lists when they will come.

Yes, there is programme called dual degree, you can join this course for Bachelor's+ Master's degree. College provide this degree with 5 year duration. Good luck.

Kindly predict your college in this college predictor. It will definitely help you to get a good college as per your marks in JEE Mains. It will guide you more better which college you are eligible for and how to apply or whether to apply in it or not. https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
All the Best.

I would like to suggest you please let her decide what she wants to do as per her interest. And, if she can improve more, then she can opt for any NEET coaching so that she can crack NEET exam or any other medical entrance exams like pharmacy, nursing, bio tech. And, if she is not interested in medical then she can opt for BCA+MCA, BBA+MBA, B.Tech agriculture. But, please let her decide.

Yes, why not you're eligible to take in Chandigarh University. Admissions are going on so you can either visit their website i.e cuchd.in or visit campus for direct admission and you'll have to visit block -9 of cu for admission purpose and rest they'll guide you properly. And one last thing kindly talk to some seniors who are already doing B.com from CU. I think they can guide you much better about inside stories of the campus (Chandigarh University).