Engineering

It depends on your interest in which specialisation you want to study more, for a placement perspective software jobs pay more than core; but placement is not that important to find your passion and do specialisation in that you will be paid well off.

It depends on the authorities to provide seats or not one cannot do anything about this, focus on target instead of looking at seats.
All the best!

Yes you can. After completing Diploma from Mechanical Engineering you are eligible to purser BE in Computer Science and Engineering.

It depends on your interest in ECE or It if you are not sure about it. I recommend you to go with ECE as around 70% of companies allows ECE students to sit in IT placements, moreover. ECE is also known as evergreen branch as you can apply for IES exam and private sector job doors are also open for you.

Only if you are interested in Tech fields, Programming, Data Science, and others, or any one of them don't come in B.Tech for placements or influenced by news reporting huge demand in tech, remember reason why you have started B.Sc. And why are you leaving it.

This college is private with fee structure of 1.16 lpa.

I don't want to compare Mahindra University Hyderabad and VIT Vellore.

You can get it on NTA website.

Yes they consider them.

Can you please mention the college/university's name? It would be clear from the same.