A datapoint for all the scenarios mentioned. I went in the second week of Dec, during 2 days I rode it 6 times in total. For those 2 days, one was OK, the other should definitely be worse than 1/5 (standby around 6:00pm was 390 minutes).
First day was a 9:00am day. I showed up on 7:35am and there were already around 100 people there. If you are not satisfied with your position, the lines for breakfast reservation might turn to regular lines. Just keep an eye on it and go fast when they open it up. Hold before the turnstile, then hold before the bridge, but it was 8:30am when they released the last hold.
I also showed up on 7:55pm on that day (8:00pm closure, posted standby wait was 120 minutes), and got off the ride at 8:50pm. On the second day when I saw the wait time was 390 minutes I just left.
Fastpass: I had a fastpass for 5:00pm on the first day and 12:00pm on the second. I should have tried to change the time for the first day, but I did not realize that I could get fastpass for it on the day of if I keep refreshing until the second day. On the second day I got 2 more fastpasses after the first one.