Manipal Institute of Technology

No, you can not join. As per the Lateral entry programme criteria, The student should pass in 3-year Diploma (respective Engineering stream) granted by the State Board of Technical Examination with minimum 45% aggregate marks or equivalent.
So, for B.Tech CSE lateral admission, the Candidate should have passed a Diploma in Computer Engineering.

Placement wise, I think CSE is the best branch to go for. But even for EEE offered by the main campus about 70 percent of the students are already placed. Choose the branch that suits your interest, placements are always relative.

Reportedly 2 Lacs class 12th pass students from across the country appear for it. Since you have less time to solve more questions, you should be well aware of your. Therefore while booking slot for Manipal entrance exam, just consider which day would. MU OET 2020 Result Check Score And Rank.

Manipal University is a costly university and its fee is close to INR 2-3 lakhs pa. You should check the prospectus of the course provided as the fees is subject to revision for each academic session.
https://www.shiksha.com/college/manipal-institute-of-technology-manipal-university-manipal-academy-of-higher-education-3225

The aeronautical engg is in huge deamand and is a very well paid job. see the student reviews for more idea. manipal university has a good placement record.
see this link to know more about the placements record of the manipal university https://www.shiksha.com/college/manipal-institute-of-technology-manipal-university-manipal-academy-of-higher-education-3225/reviews
https://www.shiksha.com/b-tech/course/b-tech-in-aeronautical-engineering-manipal-institute-of-technology-manipal-university-manipal-academy-of-higher-education-172884

For Manipal University to pursue Biotech bio is not compulsory. You can check the institutes website for more on this. Apart from Manipal a lot of other institutes don't require Bio for pursuing Biotech.