India

Surely, you can get a good college. Try for Maharaja Agrasen or Surajmal College.

This depends on what course/campus you want to apply to. However, it seems difficult with this rank.

Hello Sanketh,
It's not the issue of percentage in your 12th that will matter for admission here but what matters is your domicile. If you have domicile of Tamil Nadu then you can think of getting admission. But there are enough colleges in Bangalore itself offering Aeronautical engineering branch. I am attaching a link that will give you the required information.
https://www.shiksha.com/b-tech/ranking/top-aeronautical-engineering-colleges-in-bangalore/49-2-0-278-0

I don't think there is any such college.

Yes, physics students can apply for the wildlife science course at Wildlife Institute of India. You are eligible for this. Also, if you are looking for something quick, there are a few short-term courses that teach you all that you learn in a Master's course like PRiMER, a week-long certificate course offered by Gubbi Labs twice a year. Do check out their website and see if they have any courses coming up soon. It is an extensive and intensive course on ecology and wildlife from the research perspective.

Yes, you can get a government college but its depending upon in which stream you are interested.