IIT

For direct admissions or lateral entry to engineering second year, you have to pursue Diploma in any engineering branch which is a three years course and after that you can pursue engineering fir 3 years.

Sorry to say but its a no as IIT strictly says at least 75% in all subject mean above 75% or 75% not less than it and as you said you are from CBSE, then you won't came in top 20 percentile because top 20 percentile of CBSE is above 85%. So, you try in any other college.
All the best.

Kindly go through the article
https://www.shiksha.com/jee-mains-news-articles-exampage.

Hello Rajesh,I feel you will in fact have a better chance of getting job of assistant professor. However, if you are interested in joining teaching profession then I would like to advise you to go in for Ph.D immediatey. Best wishes to you.

First know her interested course. There are many options. If she feel uncomfortable in IIT coaching, give her space and let her choose a good career. Other than IITs, many state board entrance exams are there and university entrance exams also there. Help her in choosing.

As less than a month is left for IIT exam. Try to revise the concepts you already studied. Don't try to work on new topics as it will be time consuming. Keep practicing by giving the mock tests and work on Time Management. Have confidence on yourself. Best of Luck.

Hello Gaurav.
Yes, you can appear in IIT JEE examination after pursuing Diploma. All you have to require is that Diploma is from government recognized institutes. Good luck.

Apart from IITs, next best are NITs (Surathkal, Warangal, Trichy, Rourkela and Jamshedpur). BITS-Pilani/Mesra are also good institutes. Other good institutes are Thapar University, Delhi University, Manipal and SASTRA. Do check the below link as well:
https://www.shiksha.com/b-tech/ranking/top-chemical-engineering-colleges-in-india/52-2-0-0-0?pageNo=2

To get IIT, you should pass 10+2 or equivalent examination with an aggregate of at least 75% marks. For SC/ ST and PwD candidates, there is a relaxation of 10% as they need the aggregate of minimum 65% marks.

You can apply for the New IITs or you can apply for the NITs.