I remember seeing that clip of Han and Lea talking where Ady was experimenting and added "breaths". I thought it looked pretty good, almost perfect.

No doubt it would require a whole lot of work adding this subtle detail to almost all of the Hoth scenes (much more than if he decides to add some extra bug-life on Dagobah, in only a few outdoor scenes), but if it could be done convincingly (key word), it would certainly go a long way in adding realism to these locations (making them less like sets). It is up to Ady if it's worth it :)