B.Tech

Well, of course you need to be very good at English vocabulary which, for me is the key point to crack the GAT paper. Apart from English, one should practice class 10th level Maths.
General knowledge is important related to every field. Not only GK, but class 10th level history, geography, general sc

It depends on the employer. Most employers like to hire candidates who have got prior work experience at the campus.

For MBA, one needs minimum 50% marks at graduation level. For full time MBA, the score that one gets in the CAT do matter more than marks as graduation level
For M.Tech, the B.Tech marks do matter.

This decision would depend on your interest areas and career aspirations.
MBA will give you exposure to business management, whereas M.Tech will give you exposure more specific to the technical area.
According the area of work that one gets will also differ.

Admission in MBA is based on open test score (CAT). To qualify for admission, one must have minimum 50% marks at graduation level.
For admission in M.Tech, the graduation score will matter as the admission will be based on merit, so the higher the score, there are chances to get a better college.

Computer and Communication Engineering has been established as a branch in the college since the last 5 years. The same companies that come for Computer science, IT, and Electronics also recruit students from this branch.

Yes, of course you can pursue aviation, but select a good institution so that you could be easily placed in.