B.Sc

Some universities do allow you to do this, so if you don't get into one program you have the chance to get into the 2nd one.
You need to get in touch with the college for more details.

Among your choices, my recommendation will be as follows: M.Sc. in CS or IT, MBA and MSW. You are advised to choose the subject for your PG based on your interests to excel in your chosen career.

It is quite impossible. If you have done B.Sc. in nursing then it is possible but B.Sc. in any other specialisation is not a requisite criteria to go for M.Sc. in nursing.

You need to contact the concern person at the institute. They will be able to describe the fee structure for the same.

At present, 10th, 12th, grad marks do not have any weightage in selection criteria for MBA in FMS, until unless you are scoring atleast 50% in each of them. However, I cannot guarantee you about the selection criteria in 2019-20.

If you have the interest and the passion, you can. You need to show your interest to the universities through a statement of interest, extra-curricular activities, any demo or project work in gaming and programming, so you need to convince them why you want to be a programmer or even a game designer from a commerce background. See, if you have prior knowledge in these areas, if not, enroll into a course. It is natural for students at this stage to explore, good luck.

Yes, if you have mathematics as a subject in B.Sc, then you are eligible for MCA.