Encounter codes work fine for me on Ryu, load the code in the school town, go out to a route and it will be one of the encounters - catch it, go back into town, save and exit then turn off code and reload
Kinda looking for clarification, but how do you trigger the sidequests for the genies? Got all the legendaries except them and can't seem to get Cogita to give me the quests
Edit nvm, just had to go back to Jubilife HQ oops