Did you read mine? Sorry, but you can't save Rue, she's dead. Finnick, Prim, Madge and Cinna on the other hand are saved because Beetee is given a special assignment to make a time machine to go back and save the people Katniss loves(he himself wouldn't go, a special team would). They can't come out and talk with Katniss until the machine is made in the current time frame. And Katniss is still convinced they died so history isn't changed. The reason they can be saved is because Katniss never actually saw them die.