I don't know if it's intentional or not but after watching that it makes me believe that Tet in some way had the power to make Shiro & Sora in Riku & Schwi's image guiding them behind the scenes of there life up to the point they get to the other world/reality.

I'm probably overthinking it and they're just so similar because they wanted the movie to feel similar but I wouldn't be surprised if later on (if they continue it) we find out that that was the case.