Yes, Jamie from Asana Support was able to fine the orphaned project and give back access to myself and the owner. She also provided this feedback similar to what you said earlier.
“For future reference, if a project has all non-limited access members and owner leave, it will be essentially be inaccessible. Please be sure to have the owner transfer ownership of the project before they leave the project.”
I think next time, it’d be best to ask the owner if there are projects that the team administrator doesn’t see. Although I’d prefer if the admin can see all projects within the team.
Thanks for your help and time.