Degree

Follow the link below for details :
https://www.payscale.com/research/IN/Job=Software_Engineer_/_Developer_/Programmer/Salary.

Yes, it is very much valid in the entire country.

There is a boom of civil engineering nowadays so I can advise you to gain the experience in construction field as experience only makes you the perfect and you can earn good package, go for training in big companies gain experience and then go for good job, try to learn as many software as you can.

Yes, you can apply for B.Ed with any graduation degree.
B.Ed. Eligibility
The minimum qualification required for entry into B.Ed. course is Bachelor of Arts (B.A), Bachelor of Science (B.Sc.) or Bachelor of Commerce (B.Com.) form a recognised board/university with at least 50% marks.
Students required to appear in an entrance test conducted by the various states and Independent educational bodies and universities for admission in various teaching institutions attached with it according to the rank of the candidate in the entrance exam.

The basic eligibility for admission to any of the B.Com. programs is mentioned below.
Candidates must pass in Higher Secondary School examination from a recognized educational boardThey should have Maths and English as core subjects
Minimum 50% marks are required at 10+2 level
Although, candidates from Science and Arts stream are also eligible to apply, those with Commerce stream are preferred.
There is no work experience required for the course. However, students with work experience can also apply.

You can persue Amie if you want persue your btech via correspondenc.

MCS or MS both are the good options after the BCS degree. It will provide you superb employment opportunities. After few years there will be very strong competition and only people with master degree will get a good job. You can also do telecom engineering. It is also a good field and it has bright future. It is totally depend upon your interest, As if you are comfortable in programming then MCA is best option for you and if you are good in management then MBA is best for you.
There are many options available but you should go as per your potential and interest.
Hope this helps.

The candidate must have passed Standard XII (10+2) or equivalent examination from any recognised board with minimum 50% marks (45% marks for Scheduled Caste/Scheduled Tribes). The Symbiosis Entrance Test (SET) 2018 is a common online test for the admission process at the undergraduate institutes of Symbiosis International (Deemed University) for admission 2018.