B.Arch

Yes, definitely you will get a seat to pursue B.Arch under OBC quota.

Hi, it's difficult to get Himgiri Zee University with this score, you can check other colleges.

It is difficult to get Sir JJ or SPA Delhi with a rank of 17354, you can check other colleges.

Hi,
You can get a seat through COMEDK if you have registered for it, or else private management seats can be taken with valid NATA score.

Yes, you can if you have secured a good rank in NATA.

Hi,
Kindly check this link of college website for details and facilities provided by the college:
http://www.capitalarch.net/Infrastructure.html

Why to go for B.Sc then? Just do the graduate and PG course in interior considering the latter part and it's done! Interior design'n is more about how much practically you have been into it and less about the degrees in your resume! There are people who are doing laurels just after taking the graduation course.

NIT does not allow admissions through Diploma.

Dear
According to me, you should plan for B.arch and do job to understand the job market in both the profile whether in Architecture or Interior design then you may consider option whether it's M.arch or MBA according to your interest and career goal.
All the best.

Hi,
You may refer to the placement section on this link as a college can be considered good if it is having a good placement record.
https://www.shiksha.com/architecture-planning/course/b-arch-indira-gandhi-delhi-technical-university-for-women-kashmere-gate-238478