Of course there are many ways to create more realistic fake voices, Melodyne, Voice Pro, Auto-Tune.
What the transport function in Inspector window can do, is very basic and limited. To create Harmony, you need a serious plugin like I mentioned above.
Like in Melodyne, to create a harmony, you not just do PITCH adjustment, you also need to do FORMANT pullback to avoid Chipmunk sound.
Good Luck!