B.Com

I hope this link will help you:
https://www.shiksha.com/accounting-commerce/colleges/b-com-colleges-Delhi-ncr.

A Few obvious choices are:Auditing -
Stat (if doing CA or Internal Audit - Risk Advisory
Banking and finance
Funds management consulting
Stock Broking.

The candidate must have the passing certificate of class 10th and class 12th. The candidate then has to apply online and fill the form and selects the option for a skype interview from the respected hometown or can opt for a personal interview in the campus.

I think so. Since top b-schools in USA such as Harvard Business School, Stanford Graduate School of Business and others may have a higher cutoff percentage; just look at the criteria and all others terms and conditions related to it. Top B-Schools in USA are Harvard Business School, Stanford Graduat

Mathematics is essential for B.Com honors from DU. You will not be eligible if you have not studied Maths in class 12th. You might be eligible for B.Com pass if you are not from mathematics background.

Yes, you are eligible to take CAT 2019.

Yes, you can do the course externally. You are eligible for the same. But, both the degree should not be from government institute.
good luck.

Shri Ram College of Commerce(SRCC), Lady Shri Ram College for Women(LSR), Hans Raj College, Hindu College, Sri Venkateswara College, Jesus and Mary College(JMC) and Ramjas College. Percentage required is more than 85%.

After entrance exam, they will soon release the admission list in June-May be then you have to go for document verification there.
Good luck.