It's only a pair of boobs if the company in response chooses to do that or obvious feedback from consumers. Guest characters on the other hand, do not fall on this category because it's asking for rights from another company. That company also has a say in the matter as they can choose whoever they want in terms to what both companies agreed upon. Perhaps any other typical game companies where they focus on strictly females is believable for inclusion. There are some characters from other users who posted here however, belong to companies that are more generally sane on the matter with who they want include if they actually worked in a collaboration.