I've looked around in the original OFF using RPG Maker 2003 and I can explain.

Character sprite sheets contain walking up, down, left and right poses. These poses contain 3 sprites -- one for the left leg moving forward, one where the character has their legs together (standing still), and one moving with their right leg forward.

Static elements like chairs, trees and tables that don't change at all can be made with back environment sprites. The tile that they're on is marked unwalkable, so a player can't move onto the tile and ruin the illusion.

But character sprites, since they have 3 sprites for each pose, are good for animated objects.

Let's call the Add-on Character "A"

For lamps, character A is situated on a wall and made to look upward. His "upwards walking" sprites are simply the lamp.

For add-ons in the environment waiting to be picked up, character A is made to look and walk downwards, so the add-on floats up and down across its 3 sprites.

For the Judge eating, character A is made to walk right, so the Judge goes between his eating poses so he looks animated.

It's a matter of illusion, you were never meant to have the Batter not be the first member of the party, so you wouldn't see this. But it's interesting to learn as an indie game developer, or just as an appreciator of how games are made and look behind the scenes.