MCA

Hi,
B.Tech is the best course because it is a 4-year professional course and it has more value than MCA. B.Tech has more demand than MCA, but if you did BCA+MCA then there would be no difference between B.Tech and MCA. But, I would always suggest you to go for B.Tech. I hope you understand why B.Tech is preferable. Remember, B.Tech is a fully technical course with more value.

You are advised to do MCA from IGNOU as you meet the eligibility criteria to do MCA at IGNOU. Eligibility criteria to seek admission in MCA is as follows: " Any Bachelor's degree of minimum 3 year duration from a recognised university and mathematics as one of the subject at 10+2 level or graduation level; else the student is required to pursue and pass the BCS12 course concurrently with IGNOU MCA".

Both MCA and MBA are good career options provided degree are obtained from good college. If you are technically oriented person and continuously ready to learn new technologies then MCA is right field for you else you go for MBA. Starting salaries of MBA are higher but total earning potential over working life-cycle are similar for both MBA and MCA graduates as software engineer have opportunities to earn and save in foreign exchange also.

It's difficult to get job abroad immediately after MCA. You have following options to go abroad: (a) Join a large size IT company and work on cutting edge technologies so that you become eligible for onsite assignments after few years experience.
(b) Try to immigrate to Canada, Singapore, Australia, etc. after few years experience.
(c) Go for higher studies such as MS or MBA in foreign university and stay there for job.
(d) Apply with a job abroad through a consulting firm or foreign job portal after gaining cutting edge technologies experience.

With BCA, you can get job in only small and medium IT companies as junior developer at lower salary. MCA is a standard educational qualification for entry into top IT companies. Unless you have personal reasons, you are advised to do MCA before taking up a job.

Yes, MCA is a different course than MBA. Although you don't need MCA once you have gained degree into MBA in system or computer applications. MBA involves a mix of technology and management, so is quite recommended.

You must appear for JECA or PGCET.

Both MCA and MCA are equally good options for B.Sc graduates. If you want to be a systems developer then opt for M.Sc and if you want to be an App developer then opt for MCA. Job opportunities for App development are more in comparison to system development in India. Lot of universities offer MCA through distance learning mode.