I was going to write this earlier before I changed my mind.
One of the quirks of the engine is that in some cases, it's programmed to load PC graphic data only from the original PC graphic banks. When it's given an address outside them, it defaults to bank D5, the one containing Ayla. I think there might have been a patch for this, but I'm not sure.
Something interesting, if you get into a battle it uses Frog's graphics again ( minus his palette)
Another one of those spots where it ignores the sprite data entries, instead using the PC index.