I am not sure how I feel about 'no chance to go back' being a part of this. On one hand, it makes the irrevocable decision clear - once you set out, there is no chance to turn around. That gives the scene a very clear 'Point of No Return,' and there is no need for the Noldor to be second-guessing themselves or for there to be a contingent saying, 'We should turn back!' the entire time they are crossing the Grinding Ice. Also, it fits well with the message of the Valar fencing Valinor against them. Just as the wind blows Fëanor's ships off the coast with a clear, 'Get out!' message, the ice could break with a clear, 'No coming back!' message for Fingolfin. The way is shut.
But....it also feels a bit...fake? to me, to have the ice just make the final decision for them. Not necessarily non-Middle-Earth, where sentient landscape making decisions for you could be a thing, but still...fake. So, I balk at it every time it comes up, and I really don't know what would make me okay with the idea. It's not a bad idea or anything, and I can intellectually understand why to do it, but there is still a part of me cringing over it. Just gotta keep mulling it over, I guess.
As for knowledge of the Helcaraxë, I think the Noldor have *no clue* how bad and extreme it is. They must be aware on some level that there is in fact a way, but do they know it's the Helcaraxë? I'm not so sure. There are a few loremaster types, and the Noldor are into knowledge, so surely someone somewhere has a map. But more importantly, the Helcaraxë is how Morgoth got to Middle Earth, and they are following him. There are some really obvious signs of the passing of Ungoliant - she left bits of darkness spiderweb everywhere. So...as they get farther north...they can pick up her trail.
Araman is a barren and desolate place, but it is not an ice desert. So...not particularly hospitable, and not a place you want to settle down, but...not nearly as harsh/dangerous/bad as the Helcaraxë. Food is an issue in both places. Let's hope the Noldor like fish.