Taran and Eilonwy have very similar faces.
The differences are:
Taran has brown eyes, Eilonwy has blue.
Taran has a line next to his nostrils that Eilonwy doesn`t have.
Eilonwy has eyelashes and lipstick unlike Taran.

With just a few tweaks I could easily have turned Eilonwy here into Taran in a wig and a dress but I decided not to.
I aleady have Taran in a dress and I can draw Taran in drag some other time but today I thought it would be Eilonwy`s time to shine.

Eilonwy (This version of her atleast) belongs to Disney.
This is just silly fan art.