Andhra University, Visakhapatnam

No it is not possible in andhra university to choose another group differnt from your diploma course.You have opt only what you studied in the diploma.Other wise you have to join as a fresher then your diploma is not valid

Yes, you can take another attempt of NATA to qualify and get admission into your desired college. You have maximum 3 attempts to NATA. All the best.

Yes, there is lateral entry programme for B.Tech.

Hi,
You can find the information here:
https://www.shiksha.com/humanities-social-sciences/political-science/course/m-a-in-public-administration-andhra-university-visakhapatnam-269564

Hi,
You can find the syllabus here:
https://www.shiksha.com/university/andhra-university-visakhapatnam/aucet-exam-syllabus?course=453

Hello,
Yes, Andhra University is AICTE approved for distance learning. All the best.

You can do MA in English, because the degree of B.Tech is completely graduate degree & MA (any discipline) can be done after graduation. So, you are eligible for MA most of the university have course of MA (english,two years or four samesters) & prefer 50%marks of graduation.
Many universities also conduct entrance exam, so you can see syllabus on official website of them.
Books are available in market (basically syllabus pattern will be same in graduation level in English subject).