Vellore

Both the campuses are not going to make much difference. You have to choose which campus you want to join in at the time of counselling.

You can use Shiksha's college predictor https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor. JEE Main Rank and College Predictor uses your JEE Main 2019 percentile to predict your rank and chances of admission in the college of your choice.

Hello dear,
According to the previous year record, closing rank for VIT, Vellore for CS Engineering is 7500 and that for mechanical engineering is 19000. Some other mechanical engineering with specialisation courses are also available whose closing rank was 25k. So, it is quite difficult to get admission with your rank however it totally depends upon VIT itself, maybe, they allow you. So, wait for the last counselling round.

With this rank, you can't get CSE. You can try mechanical and electrical branch.

Yes, the placements of this college is good, but the companies like Google, Apple, Microsoft doesn't visit this campus if you want to get into these companies then you have to talk with your seniors there in that almost everyone has contact person in these companies.

No, if you have missed the Bhopal one, then you have no option left with. But, yes you can contact to college authorities, they will surely help you out in this problem.

The only and most dreadful disadvantage of joining the Chennai campus rather than the Vellore is the environment, the people you find in Vellore is far more interesting in their respective field than the Chennai campus.

You can use the Andhra Pradesh-EAMCET 2018 college predictor option available on Shiksha. Com. College predictor helps students to get an idea about the chances of admission in the college of their choice based on Andhra Pradesh-EAMCET 2018 result. Please refer the link below for your reference:
https://www.shiksha.com/b-tech/resources/ap-eamcet-college-predictor.