I was trying to check out how many people were upgraded on flight 1829 last night SFO-EWR. The PDA list shows 7. Is there a way to know how many were on the list to begin with in order to assess my chances of an upgrade on a future flight?
No...but what you could do is check that flight on the day it is departing and watch it in real-time before it departs
Is there a way to know the status of people on the list (i.e. platinum, gold, etc)?
No...I believe CO Insider hinted that they are not going to do that for privacy reasons.
Also, when the list shows that 7 were upgraded, does that mean all 7 were upgraded at the airport or could some of these been EUAs?
Could be any combination of EUA, at the airport, mileage upgrades, and/or Y-UP upgrades.