I appreciate your interest in those two characters, however the VN is more focused on the story than the sex. Having the option to have even a one-night stand, let alone a relationship, with more characters besides the five LIs would distract from the main narrative and wouldn't add much to the story beyond more sex scenes. I understand that people enjoy more options in VNs, but the goal of By Your Hands isn't to give the player as much freedom as possible, rather to provide a specific story. That said, there will be side stories that focus on side characters, possibly giving them their own erotic content. If you want to see more of a certain character, maybe there will be a side story featuring them in the future.
