Exam

You can apply for B.Arch at KIIT even if you haven't attempted KIITEE.
The candidate needs to appear for Kalinga Institute of Industrial Technology Entrance Exam (KIITEE) exam who have not given NATA exam. You can go for the admission process. Admission is based on the score obtained in NATA.

I am not sure for 2nd round but you may get CS in third or fourth round of UPTU counseling. At 6534 rank CS in JSS it is difficult to get in first 2 rounds.

Greetings from Shiksha.
Chances are very less for getting admission in computer science engineering is PES University , but still apply for it if by chance you get admission in it.

Admission to all courses (except Ph.D.) is done on the basis of an online entrance test -"GLAET", held at 60 centres all over India. Admission to these courses is subject to fulfilment of the eligibility criteria.
If you haven't attempted the exam, you cannot get into the college.

ATMA being all India exam is accepted for PGDM course in many of the good colleges of Maharashtra for that you should have 99.9x% and for MBA/MMS program MBA CET is mandatory cutoff of which is mentioned by DTE already.

37% marks in CAT is very low score. You should at least score 85% marks and above and for admission in the college mentioned above.

You can opt for VELTECH UNIVERSITY. If you have not given JEE Mains. Placement is good there and fee will be around 55k per semester. You can call them or visit their official site for more details.

Yes, your chances are there for getting NIT, Delhi. But, I am not sure about the branch. You may have to compromise with the branch. But, NITs are good for all branches. So, you can think of it.

You cannot sit for counselling of NITs. Else, you can get admissions on the basis of your JEE score. Find a link below that will help you to find a college suitable for your rank:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
Hope this helps you.

Hi,
It is very good decision to pursue MBA. You can refer face to face MAT, S. Chand, RS Agarwal books to crack MAT.