Hi Melb2021,
1. The question is "Do you hold or have you held any nationality other than the one you have indicated above?"
It asks if you have held any other Nationality, as someone who also has an expired NZ passport (expired in 2004) and an AUS passport I filled it in with my NZ passport. I believe you should have done the same. I feel honesty is the best route. If that passport was used to travel to the USA they will have it on file.
2. University Dates, which Uni did you go to? Most have calendars uploaded online, I can imagine a rough date would be acceptable. My dates were rough for Schooling and employment. So I think you should be fine.
Regarding Doc submission, I submitted in Feb waited 4 weeks got an waiting for scheduling message. (I'm OC14XX)
One thing I can say for the NZ police certificate is to read the reciprocity page, they don't mail it to you and you need to make sure it's sent to the correct embassy where you're getting interviewed.
If you have an NZ document questions, feel free to message me directly. I had issue where I had to get my Birth Certificate corrected.