That's what I get for skipping tutorials.

[Dragnfly]

All this time I've been changing my map avatar through the tactics menu to try and trigger all the character-specific stuff like gems and whatnot. Then I accidentally clicked on the character's sprite and they change. Derp:(

[Nemomon]

Yeah, if You double click Your character on the map, they will change into someone else, so You won't have to enter the menu each time You need a specific character to change to them.