CBSE 10th

Chances are very good. Most probably, you will get a call.

No, not at all. Your talent will reflect your personality, not your marks. So, be tension free just focus on your studies, not on the marks. You have cleared the class 10th not 12th so just concentrate on your 11 and 12 only then on the entrance exam you are preparing for. Make sure that your marks don't go so down that you are not eligible for applying the entrance or taking admission in college.

Marks acquired in class 10th and 12th hold huge importance. They want somebody who has been good at studies all throughout his life and can manage the aspects of extra-curricula with the regular curriculum. People who do not have great marks though have succeeded in the past and will continue doing so. If you have the will and strength, marks do not and should not make a difference. Just ace the exam, and get to the B-School you can.
Regards.

You need to complete 12th to get started with this course.

If you are from a general category, the chances are very less, if u have a reservation you do stand a chance if at all your GD/PI performance is up to the mark.

You can apply in PGDM and you will definetely get a call for interview. More weightage will be given to your interview and personality traits and past achievements, so you have a fair chance to impress.

You can apply for study loan and continue your further studies in the stream in which you are interested.

I think your ability, your experience, skills and your perfection matters. After engineering, no one is going to check your marksheet. What projects you have worked on matters and what skills you have is something that matters.