

Students must pass 10+2 (or equivalent) with a certain percentage (60% in most cases). Individual criteria may differ by institution.
Candidates can appear for more than one exam for which they satisfy all eligibility conditions, and the schedule of exams is conducive to them.
Yes, some colleges admit candidates on merit, i.e., marks scored in 10+2 or equivalent examinations.
You should keep visiting the official websites of the exams and colleges concerned, and consider subscribing to their newsletters/notifications.
B.Com (Hons) usually involves a more focused and intensive study of commerce-related topics than those covered in the introductory B.Com course.