Yes, they all come from the R bucket. If you do an advanced search on co.com and select 'one pass reward upgrade' you can query the R bucket. If your desired flight comes up in First when you do this, upgrades are available.

As your wife is waitlisted, she should immediately clear if a seat becomes available. She doesn't have to wait for the EUA to run.

Like sbm12 said, she will be added to the standby list at check-in if she doesn't clear in advance. She will be prioritized as a Plat on a mileage upgrade (assuming the miles came from your account).