True. I doubt Eöl or Maeglin showed much interest in the Naugrim’s culture, unless it related to craftsmanship and metallurgy. I can see Finrod being the first to ask, and his findings being later confirmed by Celebrimbor’s. Though for some reason I can’t picture Celebrimbor being much interested in telling his fellow Elves what he’s learnt. On the other hand, I can picture an excited Finrod going to his cousins and telling everything he’s heard from the Dwarves.

I don’t think Eru would have destroyed the Dwarves, I think they were adopted the moment Aulë made them. What I don’t think Eru knew was what to do with Aulë. For me, that all depended on Aulë’s response.