C++

Yes, definitely you have many opportunities after learning java it is very useful in the software sector even though you are a mechanical student it doesn't make any difference.

Go to any school it won't matter, join a good coaching institute and then focus on your preparation. You will get enough time to polish your skills to get into an IIT.

I am sharing few courses you can check these and others as well:-
Animation Film Making
Animation Master
Animation Standard
3D Animation
Advance Diploma in 3D Animation- Expert
Advance Diploma in 3D Animation
Advance Diploma in Fashion Designing
Advance Diploma in Interior Designing
Advance Hair Diploma Holder
Advanced Diploma in Digital Animation (Diploma in VFX & Animation)
Advanced Diploma in Multimedia
Advanced Editing
Artistic-Basic Jewellery Design Programme.

Yes, you can apply for jobs after completing your course in C, C+ and Java programming languages if you're a good coder and have good coding skills. There are possibilities for you to get a decent job with big companies.

There are lots of institute in Bangalore, which provides very good training in programming languages.

Yes, you definitely you can. There is a huge demand of Ethical Hackers and Cyber security personnel. This field will always be there due to the increasing amount of data and servers. The risk of getting hacked is always a big concern. Moreover due to the digitalisation of the technology the risk will always prevail. Hence the demand for a person like you won't decrease rather will increase always.

For basics of a language, you can visit saurabh shukla's youtube channel. It will help you a lot.

If it is necessary to learn this language for you then start from basics. There are many free tutorials available on youtube.