B.Arch

No, there is no admission on the basis of merit because the basic eligibility for Bachelor of architecture is the candidate should clear NATA (National aptitude test in architecture) with the 80% marks conducted by Council of Architecture.

No, through only JEE Mains Paper 2 or NATA score you can get admission.

Yes, you can apply for the same. This campus accepts the JEE Mains scorecard. So, keep going.
Best of luck.

Yes, you can look for colleges under Annamalai and Bharathiar University. They offer courses with less fee and a large number of seats will be always there.

No, you have to crack the entrance exam conducted by Anna University.

The selection is based on your JEE Mains Paper-2 Rank. Last year (2017) Closing Rank for: Chandigarh Candidates : 7910
Non-Chandigarh Candidates: 2362
So if you want to get admission you need to be under the cutoff rank of JEE paper 2 then only you will have chances to get into Chandigarh college of architecture.

You have scored well in JEE and you have scored a great rank and yes, you can get a seat in NITs.

Your score is low for NITs. I will suggest you to go for private colleges.

To apply for scholarship under Post-matric Scholarship Scheme for SCs/OBCs students, please visit:
http://www.punjabscholarships.gov.into apply for scholarship under Scholarship Scheme for Minorities students, and
Central Sector Scholarship Scheme for College and University students, please visit:
https://www.scholarships.gov.in/To apply for AICTEs scholarship for J & K students, please visit;
http://www.aicte-jk-scholarship-gov.in/.

You can use this link to check your chances of getting NITs. This is Shiksha's official college predictor tool based on previous year's data.
https://www.shiksha.com/architecture-planning/colleges/b-arch-colleges-india