Electrical Engineering

Both the branches have good career growth. Mechanical will be more inclined to manufacturing, operations and supply chain. Electrical will be related to power generation and transmission industries. Electrical will also include subjects from electronics and computer science. PSUs in India do recruit students from electrical and mechanical based on there GATE scores. At the end it's individuals interest to choose the branch.

Indeed. You can pursue B.Tech in CSE after electrical engineering. Once you opt for it, you will realize that electrical engineering strengthened your basic knowledge about this field. Computer science engineering in today's time has a very wide scope. You can apply in various colleges in India which might give you an upper hand for doing a Diploma as well. For doing B.Tech in CSE, you can opt for any of the colleges:
Thapar University, Patiala
DTU, Delhi
IIT's
UTM, Shillong
These are few colleges I have shortlisted for you to choose wise and the best!
Hope this helps!

Kalinga University is one of the best university to pursue engineering. It has good infrastructure and faculty. You can get admission in Kalinga after qualifying JEE Mains exam or the entrance exam of Kalinga University.

No. You should have completed 12th board.

Engineering graduates have better earning potential in comparison to Diploma holders.

Yes, you can easily change your stream because in all engineering stream 1st and 2nd years are almost same. So directly contact your institution's administration for this.

Computer science engineering has better scope.

You should pursue. For that, score good marks in GATE exam.