Well, I'm fine with counting illusions, statues, images.
But in my opinion, every person should be counted once in a comic. With that rule it would be very easy to count out impersonations.
Still, the impersonations are rare.
So far, we had only three impersonations (one character posing as another) I can remember: Belkar as Shojo, Tarquin as Thog (4x) and Elan as Cliffport Prison Warden.
Alternate selfs and non-specific disguises are more common: Elan as Ogre, Blackwing as Mexican merchant, Celia as Darkblood Gloomgloom, V as lizard/dragon/badger...