How exactly does Enchanter Illusions work?

[Entee]

If I am a Dark Elf Enchanter and am KOS to Freeport, Felwithe, and Kaladim guards / merchants /NPCs, can I just Illusion into that specific race to go in and use their merchants, bank, walk freely through the cities?

If so, what about if I've killed their guards or other NPCs? Like for example, if I killed Felwithe guards for hours. Could I then illusion into a High Elf and go bank / sell in the same city as I was killing the guards in?