Hi there territt.
Will take a stab at tackling your questions, and others will almost certainly chip in too (perhaps with some corrections !)
1.Yes, you can upgrade if space available. Not sure of the exact cost, although be prepared for a significant amount. You should be able to check figures by going to your 'Manage My Booking' page on the EK official website - although if your booking was made with an agent, you may need to refer back to them.
2. I don't believe amenity kits are issued on daytime sectors in J. But then I'm not the best to advise on that because I tend not to bother with them anyway and often leave them behind at the end of a flight (there seems to be a mismatch between the flight numbers you quote in this question vs those quoted in your opening para ......??)
3. You have selected one of the best-regarded seats (23k or 23A generally get very positive reviews/feedback). Some have commented it might be too close to the bar (not a problem if you enjoy hanging around bars

) or that there might be a delay in your meal service but I would stick with it if I were you.
Hope that helps a little.
Have a great trip ^