I feel uncomfortable having characters go through Nan Dungortheb thrice in a season, to be honest ^^ We didn't want to deviate from Tolkien's version two times already: Aredhel goes to Nan Dungortheb on her trip to the Feanorians and Haleth leads her people through there on their search for a new home. Just going around Doriath in the south was the better idea for both of them, but they need to make a bad decision for story reasons; the same would apply here. How many justifications for going through there we can inject into our version remains to be seen. Also, in this season and the beginning of the next, everyone is suddenly going there...and then it'll barely ever appear again, which feels kind of weird.Hello good people, what would you think of the idea that Celegorm & Curufin and the refugees of Himlad/Aglon are driven to the borders of Doriath and are denied passage through by the march wardens. They then attempt to escape via nan dungortheb only to incur many losses among their people and as a last resort have to travel the long way around to Nargothrond. This will help the viewer to understand the great enmity the C brothers have for Thingol & Doriath which will bear fruit in later Seasons and maybe also show some heroics from Huan as well.
I like the consequences of your story, though I think they work without Nan Dungortheb if they ask the march wardens (I don't know why Thingol has march wardens outside of Brethil to be honest, but I don't think viewers will question it much if we don't emphasize their job description) for refuge and assistance (military, medical, other supplies or whatever) and get denied because they're kinslayers (and may even talk Quenya among themselves). Then they go the long way around to Nargothrond.