We will have to see how they handle the RPs after February. Last year they gave them a quicksell option. We don't know yet if they'll just go that route again or actually go the extra mile to make them eligible as the final card in a power up (unless I missed that clarification at some point previously).
No RP's have never been able to be added to PU's.
That is dumb they need to change that ASAP. Every other program allows nats but rookie premier. That's dumb
If not that's so wack.