Engineering Scope

Stream change after the first year is completely dependent on the college and university norms, some universities allow it and some won't plus you need to have good scores in the first year to apply for the same. For further details, contact the college authorities.

A desktop engineer is responsible for the hardware and operating systems to support business functions. They may or may not support the applications like databases, web services etc.
The network engineer is responsible for the infrastructure that ties all of the systems engineers computers together.
With 'the cloud' terms like cloud architecture and dev ops engineering seem to blur these lines a lot.

Yes, companies do come for PGPM with operations role. Kindly check the following link - https://www.greatlakes.edu.in/pgpm/placement-snapshot