OP never said that the Triplets had to be star players. In fact never even stated that they had to play in the league. Only how hard would it be to draft triplets...
If one was a female, and a team decided to use a late draft pick on her just for the story (not that a team would waste a pick like that), it becomes much easier to fathom this scenario.
Still, if she had any level of talent, even a Manon Rheaume situation. It becomes more likely that some team at least takes a flyer on her. I'd say it would have to be the same situation, expansion team looking for headlines.
Of course it's much more likely that triplet brothers would get the call. But I still think it's more likely that a single female would appear in an NHL regular season game before a set of triplets regardless of sex.
But to your rebuttal, you are arguing circumstances, but the fact is Rheaume did play in the NHL. You don't have to like it, you can argue that it's publicity vs talent, but it happened and if the right female player came along it could happen again and in a bigger way.