CBSE 12th

Taking into consideration the best of 4 subjects in which you have scored well but ensure that in those r subjects maths should be included.

There are mass recruiters that come mostly from IT companies that looks out for the 60% eligibility criteria. All the other companies have as 50%.

You can opt any courses like:
B.Sc
B.Com
BBA
B.Sc, etc.

Yes most of the colleges do nor have criteria for Mathematics compulsion. You may apply. Thanks. Good luck.

For becoming a doctor you should have PCB, but check out the eligibility as for being a doctor you should write NEET exams check out the eligibility if PCMB is required and don't ever think about being a middle class person, because if you have the passion, you can come over the obstacles thrown in your path. So, just follow your passion and then see the results all the best.

Yes, you can join the cabin crew diploma course after class 12th. Please go through the link below.
https://www.shiksha.com/aviation/cabin-crew-air-hostess/colleges/colleges-india

Yes, For B.com (hons) course, you have the 'option' to opt for economics i.e., it's not going to be a core paper. It's an elective subject and not mandatory. If you wish to study economics as one of your subjects you can choose it as your elective, else there are other subjects (political science, Calculus, Physical Education, etc.).

Fees details are as follows: INR 8.40 Lakh (Fees Components: Tuition).
Security deposit (Refundable) of Rs. 15000 is to be paid with the above fees.
The fees mentioned will increase by approximately 5% every year.
Hostel Fee Details (if applicable):
Non-AC room: Rs. 60,000/- per annum
AC room: Rs. 1,00,000/- per annum
One time Refundable (Security deposit) - Rs.10,000/- (Mess charges on actual basis).