B.Tech

You have to appear for state LEET examination to get directly into second year of B.Tech. For more details, check the link below:
https://www.shiksha.com/engineering/articles/lateral-entry-btech-a-good-option-blogId-6342.

Go through the link below for details:
https://www.shiksha.com/b-tech/ranking/top-civil-engineering-colleges-in-Maharashtra/53-2-114-0-0
For colleges in Gujarat, filter the state in the above link.

You need to opt for AP EAMCET to get admission in Acharya N.G. Ranga Agricultural University for B.Tech in agricultural engineering
Details below :
https://www.shiksha.com/b-tech/course/b-tech-in-agricultural-engineering-acharya-n-g-ranga-agricultural-university-rajendra-nagar-hyderabad-85923
https://

Yes, you can surely ask for a termination letter from the universities and get admission in any other university of your choice. BCI does't regulate these. Don't worry.

Yes, you should and work hard to increase your average.

Eligibility criteria for this college is-
12th min-50%
Mandatory Subjects : Mathematics, Physics, Chemistry
Candidate must have passed 10+2 along with mandatory subjects from a recognized board/university or authority accepted by the syndicate of the Anna University as equivalent thereto are eligible t

B.Tech and BE both are same. There is a little bit difference. But I will prefer B.Tech.