Some of the cast who were of the same height as Isabelle Fuhrman while in frame had to wear tall platform shoes while standing next to her to make her appear shorter, acting as forced perspective.
One of this film's goals as a prequel was to cover up a much criticized plot hole in the first film, which was how exactly did Esther get from Estonia to an American orphanage without having been dropped off by anybody. Even with forged paperwork, Esther would not have been able to simply show up with it.
Filmed from November through December 2020. Isabelle Fuhrman was 23, which makes her closer to the age of Leena (the true identity of Esther) than when she appeared in the first film, where she had turned 11 during filming.
According to director William Brent Bell, they didn't use a lot of digital effects to do this, instead using makeup, forced perspective, and a body double for certain shots.
In a 2022 interview William Brent Bell detailed some of the techniques that went into shooting Isabelle Fuhrman: "Every shot, no matter how simple, was NOT simple. Everything was complex, everything was a magic trick. And for the actors themselves, they couldn't act a normal way. If they're walking and talking with her, well, she's probably 3 steps BEHIND them, to make her look small. Forced perspective. Or they're up on a platform, or they're wearing 'Gene Simmons' boots. You know, it's all these great tricks. Having such a great cast, everybody bought into it. We had 3 body doubles and Isabelle was always off-camera any time we had a body double and was doing the dialogue with the actors as if she was on-camera."