Ah, I am starting to understand the issues at play here.
In the original story, Aredhel has no contact with the Sons of Fëanor until she leaves Eöl and Nan Elmoth. She specifically visits Celegorm and Curufin while they are away, so she never sees them. So, one could conclude that if she had had contact with them, they may have attempted to intervene with her situation - or at least warned her away from Nan Elmoth.
Here's the thing, though. If she is happily married to Eöl, or at least convinced that the marriage is a good thing even if her husband has some rough edges, what type of intervention would they make? Are they going to...kidnap her back away from her husband? If she doesn't want to leave Eöl, they aren't going to be able to talk her into it, and they aren't going to want to force her away from him, I don't think. They'd be unkind to Eöl, sure, as they disapprove of his marrying Aredhel without talking to her family, but they wouldn't want to kill him to save her if she doesn't want to be saved. I am sure they would want to check in with her, make sure she's okay, but I'm not sure they would go much beyond that without her asking for help getting out. The conversation between Curufin and Eöl in the book happens after Curufin is well aware that Aredhel has left him.
So, let's look at the situation. This meeting would be very early in Aredhel's marriage to Eöl - before the birth of Maeglin. So, the question would be what else is going on in East Beleriand at the time? The attack on the Stockade is the most significant thing, and might be in the same episode. Obviously, Caranthir is involved in showing up for the end of that battle, but the dwarf road may play a role, so it could tie into the dwarf/elf story we're trying to tell with Eöl as well. Amras, being the wandering brother out of the loop, might be a good candidate for who they meet up with, but Curufin and Celegorm are the closest. I think that, whomever we choose as the Fëanorean she meets, that person has to decide to let her go, because she insists everything is fine.
It will not be a matter of information not reaching the other brothers in time - Aredhel is going to remain trapped in Nan Elmoth for the next 40+ years. So, they have to know she's there, but what they will not know is that she's not there willingly...since she insisted this was what she wanted last they saw her. They are going to be very angry when she escapes and they find out she's actually been kept against her will...but they won't find that out at this early meeting.