Its not impossible that they could have their own chapters added in the story and its also possible that their chapters are part of the base released but locked until you buy them...
@Mayor-Of-Mustard Well, i was saying that on DOA5 Marie was DLC, and she didn't had her story. Could happen again on DOA6, But i really hope they have stories. And decent ones this time. (Ah, btw, remember when you said Faceapp Marie and Teletubbies Bayman would fight? It's happening cannonically on DOA6. Lmao.