Granblue fantasy

Are there any artworks featuring them?

It didn't appear in the anime. There are a couple of ambiguous scenes, but I don't feel like looking for them.

Added 1 minute ago

Specifically, there isn't that kind of explicit content that Ples described in the "Granblue" game.

Well, both Chariot and Nina have been added. But they aren't in a hurry to add Favarro and Kaiser. However, they aren't needed (just like other characters from the anime, for that matter). It would be better if they added Sophie.