I am replaying but I cannot remember how you meet tsukiko, I also think there is a bug since I cant finish Iza's part of the main quest and still dont have her character card after taking her to the festival
To unlock Tsukiko you need to find the rabbit in the festival and follow it and the encouter will Start, to finish Iza's you need to do that, so go to the dojo and talk to Izanami to go to the festival and it will start.
