Binding Flash's monk skill and runes could affect elite enemies in a different way. But which enemies are considered "elite"? All those colored? Bosses and mini-bosses are also part of this group?
As far as I have found, the best formal definition of this actually comes from your achievement log. If you look, there are achievements for killing X number of Elite monsters (either in coop or solo), and it defines them like this:
As mentioned in the question you linked, champions are the blue-highlighted/named mobs, who come in packs and all have the same abilties. Rares are the yellow-highlighted/named mobs, who have non-rare mobs nearby with the "Minion" attribute (and may have some of the abilities that the champion has). Uniques are the purple-highlighted/named mobs, who will always appear in certain locations.
While bosses are not highlighted purple, their names are purple - they do fall into the category of uniques.