JEE Advanced

First of all, congratulations brother!
Of course yes. You will get aerospace in any one of the IITs you want because your marks are damn good in Advanced.

Hi,
Kindly use Shiksha's college predictor.

Institutes like Aakash, FIITJEE help students like you and me who prepare for JEE, they charge you according to your marks obtained in admission test, the better you do less they charge or else better you join IIT programme in your college they may take 5000/-for your books or else you can even get

Yes, you can appear for the 3 subjects. Clear the requisite of 75% marks as said by JEE Mains.

Use this rank predictor:
https://www.shiksha.com/b-tech/resources/jee-advanced-rank-predictor

It's too difficult to get a seat with this score. You need 200 and above to expect a seat in IIT.

It's possible. If you are passionate about this, go for CS and learn interdisciplinary course through online education.

Since you are from SC category, you can get a seat if you have a score of 100 and above in JEE Mains. I don't think it's good to drop a year.

They give priority to both. Both the admission processes are different. If you are from MH then it's better to go with MHT-CET.