Andhra University, Visakhapatnam

No, you are not eligible.
AU is the topmost university in the AP. Only top rankers will get the seat in that college and your rank must be in the range 3000 or below.

If you qualify AUEET, you are eligible to get a seat in Andhra University. Admissions are done through both the exams.

Yes, but make sure that by qualifying in AUEET you are going to dual degree course. Anyway, I think there is a provision for quitting the course after completing your 8th semester and to get a B.Tech certificate. But be sure about it. It's better to contact AU admissions desk for more information.

Andhra Pradesh-EAMCET 2018 College Predictor
Use your Andhra Pradesh-EAMCET 2018 rank to see where you can get admission at the link provided below:
See the courses, colleges & rounds you may crack. The result is based on admissions data of Andhra Pradesh-EAMCET 2017. Get resources & insights on colleges & courses. Regards. https://www.shiksha.com/b-tech/resources/ap-eamcet-college-predictor.

You might have a chance if you have any reservation criteria else give it a try.AU considers a very better score than this.If possible try for other affiliated institutions which follow the same syllabi pattern.