Diploma

You are eligible to seek lateral entry admission in B.Tech Aeronautical Engineering after Diploma in E&TC. You may evaluate Manipal University for doing B.Tech Aeronautical Engineering.

Yes, you can, but it'll be better to do it in offline mode, if you are doing a job then the online mode is considerable.

Do you have any specific field of interest like Sales and Marketing, HR or Revenue Management?

No, there is no AIIMAS branch located in Bangalore.

Hyderabad Aviation Academy and Hospital Management.
Trade Wings Institute of Management.
Rajiv Gandhi Aviation Academy.
Fly Air Aviation Academy.
Aptech Aviation and Hospitality Academy.
For your reference, these are the best colleges in Hyderabad for Diploma in Aviation.

There are so many top college in India which are renowned for their metallurgy departments. It depends in which state Do you want to study. It's always better to study from a renowned institution in such fields.

Yes you are eligible. You can directly go for 2nd year. Try to your lateral entry admission from a good renowned college. It will be helpful for you in future to get placed in good fields.