JEE

https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
Follow the college predictor.

Hello Chetan, If you don't have the eligibility marks in board exams, you cannot attend the official counseling conducted by them only. You can apply for other colleges which doesn't ask for more board exam scores. As well as you can apply for colleges with your board exam scores alone.

Hello Chetan,
Since there are a minimum marks based on your categories that are ought to be scored, if you do not satisfy them, then you cannot get admission through the official counseling conducted by those universities only. However, you can apply for other colleges that don’t ask for more board e

It's not possible for you to get admission in SPA. It's better to go with other private colleges.

Yes, this college takes admission only through JEE Mains score.

Yes, you can get a college in Rajasthan State government colleges and also in private colleges by donation.

I would suggest you to apply for NITs as they are the top institutes in India. If you belong to Tamil Nadu then you can get admission in NIT Trichy. Else, if you belong to other state then there might be quite less chances get you to get there. However, it is not a problem, you can get admission in

It is not possible for you to get admission in a government college if you are a general category student, you can get admission in private institutes. To know the college’s list, use the predictor tool:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor.

MCA is a PG course. In order to pursue any PG, you need to complete UG like BCA or B.Sc in computers.

It is quite difficult for you to get admission in JJ School of Architecture.
It's better to try in some other B.Arch colleges.