Electronics Engineering

You can do Microsoft (MCSE) or Cisco certifications (CCNA) or Big Data courses (Hadoop, Python) or Business Analytics (R, SAS) and so on as per your interest in that domain.

NUS and NTU are both highly reputed universities. 69.9% sounds a little low to me for admission in these universities. But if you have other factors to complement your profile like work experience, projects, research work, extra curricular activities, etc. then you definitely stand a chance.
All the best.

If you are planning to go for higher studies after B.Tech, then opt for electronics engineering. Electronics engineering has very narrow scope in India. You should opt for B.Tech in IT or CSE instead of electronic engineering.
B.Sc in IT is also a good course, but you will get benefited by pursuing B.Tech.

If you are looking for a long term and you are having below 60% in PCM in 10th and 11th, go for BBA, BCA, B.Sc (Agri), etc. If you are having above 60% in PCM in 10th, 11th go for B.Sc (Physics, Math, Chemistry) as per your interest.

1. You should apply for government jobs like BEL, Metro or BHEL.
2. If you want to further study, you should opt for Bachelors in technology.

Yes, you can change contact to registrar or exam cell.

Both the streams are good for studying and it depends upon your interest but as per career prospect, electrical is better than electronics because in India the number of electronics industries are limited.

Marketing and finance are the best specializations. You need not to go for distance mode as it is seriously not recommended. You should only opt for Full time MBA course from top 50 B-Schools.
You have to appear for any entrance exam like CAT/CMAT/MAT/GMAT/CET following by GDPI rounds to get admission into.
Fee structure varies from college to college.
Check below top MBA schools and their details.
https://www.shiksha.com/mba/ranking/top-mba-colleges-india/2-2-0-0-0