Delhi

No, you can get in architecture branch of any NIT GFTI by only means of paper 2. In fact it doesn't even matter if you qualified paper 1 or not. But you can give NATA test through which you can get good colleges in arch.

Delhi University.

If you get admission in any of the colleges in DU, you are lucky as the cutoffs are quite high and you are actually competing for 54000 seats with 2.5 lakh students applying for it.
If you want to see the DU own ranking, check here.
http://delhiuniversitycalling.blogspot.in/2011/03/delhi-university-colleges-ranking-based.html?m=1

I would suggest you to opt Delhi University as your preference. Colleges associated with DU admits students on the basis of cut off which will be published after CBSE 12th result is out. Usually the first cut off list for good colleges starts from 99%.
There are various colleges in DU which can be ranked higher for BSc like Hanraj, Ramjas, kirori mal etc

FIIB , NDIM, Amity and jaipuria noida are also good institutions accepting MAT score

Generally 15% of seats are allocated for non Delhi candidates in GGSIP university.

Delhi university is good for chemistry. try Stephen's college.otherwise prepare for IIT JAM for pursuing m.sc in chemistry.it gives u vast scopes.try to secure good rank to get into IITD