Jamia Millia Islamia

It will be declared as per the dates on the official website of JMI.

Yes for sure, you can join the university ASAP. Also, apply online to the admission process to pursue your favorite course.
Best of luck.

Admission in Jamia Millia Islamia is through JEE score, whether for engineering or architecture.

For what course exactly?

Appear for JEE and fill Jamia's form and secure a decent rank.

You have to appear for JEE Mains to get a seat in Jamia for B.Tech and also, fill their form which will cost you Rs 500.

For which course exactly, please be more specific.

I fear not, no one is clear with the percentile system still, but if we look at the rank then it is not possible for you to get admission as for the general category the seats closed for 2800 rank I guess or 3000 for the SFS batch for general category.

There is no such thing as placement, especially in B.Arch top institutions like SPA and IIT's. NIT's do give their students campus placements but that too really few in number, normally one gets a job after completing an internship programme for an architectural firm.