Commerce

as per UGC regulation of 2009 and 2015, any institute cannot offer PhD in distance mode it has to be either full time or part time with certain condition attached to it. A PhD degree through distance learning is invalid. few private universities offer such options but those options are bad for you and your career. yes, you can do PhD from your workplace but at least 6 months you have to spend in college/ university frequently for pre PhD coursework

Go for MBA, because management has more opportunities than CS. If you are average in studies, but good in communication and outdoor activities. Choose marketing in MBA and in your Bachelor's degree go for BBA or BMM. First, introspect yourself and do analysis. If you don't want to study much, then opt for courses which you can enjoy.

You should opt for PCMC.

Yes, it is fine about whatever you want to do. Commerce is also a good field. You can pursue your graduation in commerce even if you are a biology student.

You will need to check with the eligibility criteria of the college, which you are planning to take admission into. You should be able to make up. Still, consult with the college authorities.

Yes, you are eligible to take admission in B.Com (H).

Hello Rohan,
Please refer to this link to get more insights of the colleges and branches.
https://www.shiksha.com/resources/college-comparison.
However, Bharti Vidyapeeth is better.