Bought seat reservations from RailEurope, the tickets sent are from Trenitalia, which is good. I found that I can search for my Reservations then the results allow me to Add to Apple Wallet. Works great for my ticket, but my wife's reservation does not get up in her wallet, it puts mine in her wallet. Even though I select hers, which has a different CP number (6 digits, last number is 1 more than mine) while in the app on her phone and select her rez, to "add it to her wallet, only mine goes in there. Which I am fairly sure will prevent her from sitting in that train.
Is there a trick?
This will not prevent her from sitting in that train. You don't need a ticket for that, you only need to be able to find the entrance.
At the entrance the the platform there may, or may not, be someone glancing at your phone to determine that you are indeed supposed to be there. Then on the train nobody will care if you sit in the seat that is on your wife's phone and vv.
When I travelled in Italy I just used the Trenitalia app, and had the tickets in there. And then I showed them when we entered the platform area, and then later again on the train.
What may be happening is that you believe you have two tickets, but you in fact have one ticket good for two persons, and linked to your name. Different railways do this differently, but for example I am currently on my way with my wife and here name isn't even on the ticket. Railways don't care who travelled, they only care that people who travel have paid. So don't overthink this. You have tikcets for you and your wife, and a way to show them, so you are fine.