"Kiss me if you can" is one of the shortest stories of the author, but as I said there are side stories, currently three. Two of them kind of continue the plot of the main story.
The children and Josh have some appearences in the extras of "Kiss me liar", but a few of them are not adapted to manhwa so far. And both will have a few appearences, especially Josh, in Grayson's story "Desire me if you can" which will get a manhwa adaption at the end of the month.

The fact that were halfway done with this story is crazy to me