here's all you need to know about the situation above: as a 1P, you will not be in the first class cabin on this flight with it booked 18/20 at presumably >T-30 minutes to departure. trust me, i live this reality every time i fly UA now.

it doesn't particularly matter how people got onto the "confirmed upgrade" list unless they don't show up for the flight for one reason or another. once they're on there, they're gonna be riding up front unless they miss the flight or voluntarily downgrade. if you aren't on that list, you're vying for one of the 2/20 that is not "booked". in that situation as a 1P if you are not #1 on the list you probably will not get upgraded, since you will be fighting kettle TODs up to T-30 minutes before departure (the check in cutoff mentioned above).