UPSC Eligibility

Yes, correspondence degree is eligible for UPSC exam. But it should be from a recognized university like IGNOU. People has already cleared UPSC exams, who had studied from correspondence course. Best of luck.

Yes, because it is also a recognised university.

Step 1: determine your mind that you are ready to give your heart and soul to it. Even ready to spend 1 to 1.5 years with reading.
Step 2: determine if you want to take UPSC coaching or self study. (My suggestion if you have your blood relation know about or in preparation of UPSC take their suggest

Yes, you are eligible for UPSC.

No, for UPSC, economics is not compulsory.

Probably no as you need to have a AICTE approved degree.

Yes, you are eligible, if he has done BCA from a recognized college/University by AIU. Further, BCA is an undergraduate degree, hence you are eligible if meeting the other criteria.

Yes, you are eligible for UPSC. The eligibility criteria of UPSC is a Bachelor's degree from a recognised university.

Yes, you are eligible for appearing Civil Services Examinations.