If Short Round were to come back, it should have been at the wedding scene in Crystal Skull. I know that things have changed on a meta level, with Ke Huy Quan not only getting back into acting but being super successful...but, still, that was the moment.
That said, when I heard the rumors that there had been some re-shoots to the ending (not to dredge up a whole big debate from another thread about that), I kinda thought Shorty was coming through the door with Sallah the first time I saw the film. Ah, well...probably for the best, as a quick cameo in the dying minutes would have just felt like fan service, esp when the Indy and Marion relationship needed to be focused on.
As for Helena: she was great! It's very funny to watch the anti-feminist crowd try to wrap themselves around the "they brought in another MARY SUE girl character!" about someone who was very clearly flawed and broken who kept screwing things up until Indy taught her there was more to life than fortune and glory. (Not that any regular ol' person is wrong to dislike her...she is designed to be abrasive and irritating at times. But, well, a certain type of person went into the movie needing to hate her, and their narrative didn't change even when they saw how the story was told.)