Hi there Stardust,
I have read your story and I want to say that I have never seen such persistence. I am really sorry that the University is not approving. One thing that stuck out to me is that you never stopped trying, and kept a positive attitude.
I am starting a local myself, however since there are 7 NPC Sororities, all 4 NPHC sororities, and 6 in the Multicultural Council (plus one colony on the way), I decided to make mine community based and not through the University rather than collegiate based.
You seem quite passionate to create a sorority, have you considered making one for the community instead? That way, people who were at the University could still join AND you could reach out to nearby college students who cannot achieve having Greek life on their campus?
Doing events and booking tables would probably be hard, especially since it mostly belongs to collegiate orgs, but you seem to want a sisterhood and I think it could be a good option for you, especially since you are about to graduate.
Congrats on your undergrad program btw