Degree

For the admission procedure, you need to visit official website and submit it and fees is around INR. 1,10,000 for one year.

Yes, it's degree is valid, as it is a national University.

The candidates must hold a Bachelor's degree of a university incorporated by an Act of the central or state legislature in India or any other educational institution established by an Act of parliament or declared to be deemed as a university under section-3 of the university grants committee act,1956 or possess an equivalent qualification. Also visit www.ugc.ac.in.

Contact the University personally. They will help you. However, it is pretty long time since 2007. So, I am unsure about it.

Yes, no matter what college you graduate from, the certificate is going to be a generic DU certificate but you might be asked during job interviews which particular college you graduated from but that is a far-sighted occurrence.

Yes, you can do it from distance learning programme, in Delhi from 'IGNOU'.

Hi Aman, Please find the link below for detailed information on the same:
https://www.shiksha.com/hospitality-travel/exams/oberoi-step.

Hello dear,
On the basis of your class 12th, you can appear in JEE exam. On the basis JEE scorecard you can get admission in BE/B.Tech. Good luck.