Architecture

Yes, and congratulations.

Check it out here:
https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor&ved=2ahUKEwiz1-Ckk7TbAhXLq48KHUJKCFQQFjAAegQICRAB&usg=AOvVaw1N9BzFtyUCP4JU-2UQHQ0H

For the B.Tech exam, you have to opt for only paper 1, but for the B.Arch exam, you have to opt for both papers.
Based on both papers, marks are evaluated and ranks are decided.
Rest wait for the results.
Best of luck.

Yes, you can. Go for the counseling and wait for the last round. Till then, lock a seat at the first college what you will get and then wait for your turn. There may be a delay but you will get a good NIT. And if you don't get an NIT, don't feel sad. There are other government colleges also which would be a good choice.

You are eligible to apply for private colleges which accept JEE scores. Also, you can choose autonomous or deemed campuses.

Yes, you can. But the score should be good. Other wise it will be difficult for you to get into a good tier-1 campus. You can try Acharya NRV, Dayanadasagar, etc. with JEE Paper 2 score.

You can try searching colleges and branches using college predictor as it will give you a better idea. Feel free to ask if you have any other doubt.