I also ♥ Final Fantasy IV, which is why I'm sharing these scans of the (Japanese PlayStation version of the) game's instruction manual.
Here are Amano's depictions of Dark Knight Cecil and Paladin Cecil:
Cain and Rosa:
Edge, "Foo-Soo-Ya" (aka FuSoYa), Palom, Porom and Yang:
Cid, Gilbert, Rydia and Tella:
I'm particularly fond of Amano's rather effeminate take on Tella.