I'm going ORD-GEG next week and bought the ticket for the first flight of the day at 6 AM (thru SEA), as it was $120 cheaper than my desired 5 PM departure. Will SDC open up at midnight six hours before my flight, or when I check in 24 hours before? Additionally, if I am upgraded into F on the original flight, will I be moved into F for the SDC or just moved to waitlist? And regarding the waitlist, as MVPG, will I be at the bottom for last purchase time or will I still be with the other MVPG in the same fare bucket?

Thanks - hopefully, this makes sense.