Gladly enough the Nikita's Smoke Powder does work on large and huge figures so no issues there.
I recently had someone tell me for Raelin's aura that the figure getting the boost needs to see Raelin not Raelin seeing them. We were mid match, Raelin was flown far away from the rest of the army and it only happened on 1 occasion so I just went with it looking up the ruling afterwards. In a game like this there will totally be interactions like this all the time. Forgotten triggers, ability used unintentionally wrong. What really determines character is what the players do when a case like this comes up and I'm convinced the great Heroscape community is very self-policing about stuff like this.