"Came back" is a phrasal verb. "Word came back" is an idiomatic expression based off of the phrasal verb, but you can use the phrasal verb in other ways.
The dentist gave her an injection after the surgery, but a few hours later the pain in her jaw came back with a vengeance.
It wouldn't be wrong to rearrange the words as in your example. It would just be more awkward, because it places the prepositional phrase ("in her jaw") farther away from the noun it modifies ("pain"):
... but a few hours later the pain came back in her jaw with a vengeance.
It also moves the adverbial phrase ("with a vengeance") farther away from the verb it modifies ("came back").
It's good writing style to keep modifiers close to the words they modify. However, in your example you have to decide whether it's better to do this
... after word of her successful outcome came back
or to keep together the idiomatic expression:
... after word came back of her successful outcome.
Both sound fine. Which sounds better is just personal opinion.