There has been a game developer post.
What google translate tells me:
You can choose between the main characters shown on the cover. And to that, you can choose a support character...
those are currently: Kaz, Haas, "Ari" (not sure if its meant to be airi or ari short for eiraheeari), Lorraine and Ruche. ( i think it says main and support have different tasks to accomplish then?)
The setting is chapter 1 to 50, so no Ran yet. but the game is supposed to be updated with time.
it is independent of the webtoon story and character relationships don't matter (for example leez hates maruna, but in the game that's not important)
and no grown yuta of course.
ah, and seems multi language support is planned "soon"
and it the game will be at google play store then... (ha, these infos are from an answer on meg's introduction post XD)
Yeah! at least they thought to give support to English soon ^^ I'm waiting anxiously!