I haven't encountered that one yet, I actually didn't know about that one tbh, prob message the developer on their Patreon for quicker response if you really need the info, I just played all routes until I got those 4 which I thought were all it. I know there's nothing for Charlie, Willy or any other NPCs yet. Only saw one CG of Charlie in bed in his room on one of the first couple of days, he's on the first floor opposite of Kevin's room right by the bathroom.