I would book the flights and upgrades now, and then get your reservation and upgrades updated with your new status. The only thing that would change on your reservation would be boarding class and seat selection as now you'll be able to choose Main Cabin Extra. Definitely book the flight now as you'll never know how long that fare will last. In terms of the upgrade, it matters when you book the flight and also when you request the upgrade.
You need 1 per 500 mi. DFW-ANC is 3043 miles so you'll need 6 per segment because of the 51 mile "grace period." You will pay for each segment separately as you may not clear for some segments. Whichever you don't clear for, it goes right back into your account. Its weird they take it out of your account before it clears. I guess its a cheap way of checking if you have enough certs and also accounts for multiple reservations with multiple upgrade requests.