Lady Shri Ram College for Women, University of Delhi

Firstly, it depends on your category.
If you belong to general category, you can't get admission in any north campus college.
But you have a chance to get admission in off-campus colleges such as Satyawati Evening College,
Swami Shraddhanand College, etc.
For further information, you can visit DU website and have a look at the last year's cut-off.

Yes, sure. For other details, you may check the prospectus of MA English DU:
http://www.du.ac.in/du/index.php?page=m-a-english

Please refer the link for details:
https://www.shiksha.com/mass-communication-media/journalism/course/b-a-hons-in-journalism-lady-shri-ram-college-for-women-lajpat-nagar-delhi-52394

Please refer the links to know about the detailed process: https://www.shiksha.com/humanities-social-sciences/economics/course/b-a-hons-in-economics-lady-shri-ram-college-for-women-lajpat-nagar-delhi-52368
https://www.shiksha.com/humanities-social-sciences/economics/course/b-a-hons-in-economics-shri-ram-college-of-commerce-maurice-nagar-delhi-110682

Yes, you can because eligibility to MA in English is:
Minimum 50 percent in Bachelor's degree from a recognized University.

Let me start by telling you a little on what Economics is all about and how is it linked with Math and Statistics.
Economics is a social science. What makes it different is its use of maths and statistics to prove theories and concepts while still incorporating other subjects, such as politics, philosophy and geography. It is basically a statistical data which needs computing to get results.
Thus to study Economics at the Undergraduate level math is compulsory.

Lady Shri Ram College for Women does offer MA in psychology. This course is of 2 years duration. For further details regarding this course please refer to the link provided below:
https://www.shiksha.com/humanities-social-sciences/psychology/course/m-a-in-psychology-lady-shri-ram-college-for-women-lajpat-nagar-delhi-88547

You cannot apply separately for LSR. There will be an entrance examination that will be conducted by the University of Delhi, you have to fill your preferences in the order and then according to the merit, you will be allotted a college.
All the best.

The minimum aggregate required depends solely on the cut-offs which are released. You need to score around 96% at least to get admission in LSR. Last year, the minimum was 97%.

Terms and conditions for B.Com. (Hons.)3 Years
Qualifications- 10+2 and equivalent with min 45% marks
Procedure- cut off based.