While Flandre and Koishi are often paired together the same reason Remilia and Satori are often paired together... I don't think these two have ever interacted in canon, right? 🤨 Satori only met Remilia and Flandre. And Koishi had only just a brief appearance early in FDS until recently.
Flandre has definitely (or possibly, because it's Route A and Route B) interacted with Okū though, going by Sunken Fossil World.
