Company Secretary

You should clear class 12th to join the course. But, by the end of the course, you should have completed your graduation as well.

No one can tell you about this. You have to go by your own interest. Although, both are almost related to working in corporates. MBA will get you a job after 2 years. So, research about it nicely and go by your interest.

Both are professional courses. You can do whatever interests you the most.

There is acute shortage of good experienced computer science graduates abroad particularly in USA, UK and EU. This shortage is fulfilled by IT companies by providing experienced CS resources on staff augmentation mode from India. Good experienced Indian, CS professionals are able to get good jobs abroad. However, there are visa restriction challenges, which may damp your plan for job abroad.

Yes, you can. After completion of CS foundation, one may register with ICAI-IPCC and get enroll as IPCC student either with first group or both groups.