Jadavpur University

Hey buddy you can use this link to find out which colleges you can get from these marks. This is shiksha's official college predictor tool based on previous years data. Hope this helps. All the best.
https://www.shiksha.com/architecture-planning/colleges/b-arch-colleges-india

Yes, you will get a seat in the same campus. The previous year's statistical shows, you have a very high chance of getting into this campus.

For admission in Jadavpur University, architecture department WBJEE GMR(General Merit Rank ) is necessary along with qualification in NATA. That means only NATA score is not enough for admission in B.Arch, you must appear or have had appeared in WBJEE and secured a good rank. FYI last year i.e. for 2015, opening and closing ranks for general category were 861 and 4767 respectively.
Hope it helps.

Admission is based on the marks obtained in 10+2. Interested candidates can apply online with required information. Please check for your eligibility to apply for B.Sc. in Mathematics at this college from the criteria mentioned at the link provided below:
https://www.shiksha.com/science/course/b-sc-in-mathematics-jadavpur-university-jadavpur-kolkata-273121

No, you can't. If you got 3577 in GMR, then you can a chance in Jadavpur University. Please share your GMR for a good college.

Yes, you can easily get admission in the 1st round.

Sorry, but you can't get any branch in Jadavpur University if you don't belong to West Bengal. If you belong to West Bengal then also you can't get chemical but yes, you can get any other branch.