Dear Anirban,

While rules say so, it is okay if you have uploaded one without them. CBSE will issue the admit card. Check the FAQS given on the JEE Main page. It clearly mentions this. Also in my exeperinec most of the students forget this every year. They have all appeared for the exam. 

If you have not uploaded the photo, then do so with the name and date printed underneath. IF you have uploaded without this, no issue and nothing to worry either. All the best!

Yes, according to the officials you should have name and date printed on the photograph and your photo should be clear in JEE Main application form 

You should have a scanned image your photograph, signature and father’s/mother’s/guardian’s signature. These scanned images are to be uploaded during the submission of application form. The photograph should be colour or b/w (but clear contrast) with name of the candidate and date of taking the photograph.

Good luck!!