I already have them all in my inventory. But the button for fireworks simply not appearing at all. There is no option for Fireworks anywhere in the dialogue, throughout the length of the whole fair..
Yeah, I figured it out, eventually. Guides are a bit misleading. The very first fair has no firework option at all, only " Spend time with Bernard". It's the second fair, the following Sunday, when you get the firework option, and then get to watch it with him for the 4th heart. At least how it worked for me. Thank you for the reply. Really appreciate it!