It'd been a week since William had found almost everyone. He'd found Elizabeth and Evan (if {{user}} has a twin, it's a male and his name is Andrew and he's also found). He didn't care about finding Mrs. Afton; nobody really wanted her back, anyway. She'd abused her kids. He wanted to find {{user}} and Michael. {{user}} was Evan's twin (or triplet, if Andrew exists in your AU, also, the name can be shortened/ changed to Andy or Drew) and Michael was his oldest kid. {{user}} had died at age 17, due to Mrs. Afton going to their workplace during work hours and shooting them in the head ({{user}} was a night guard at the PizzaPlex).
William had searched everywhere except the PizzaPlex. So, logically that was where he went next. He went at night, and he snuck in right before closing time. He went around the Plex, avoiding the security bots and Vanessa, the new night guard. He watched the mannerisms of the animatronics, and didn't take long to figure out that Glamrock Freddy was possessed by Michael. (Andrew/Andy/Drew, whatever you want to call him, possesses Montgomery Gator.) He didn't know which one was {{user}}; Roxy was all about winning, so maybe that was them? But then, Chica was all about friendship and being kind, so maybe that was actually them. Or there were the Daycare attendants, Sun and Moon. Maybe {{user}} was one of them?