Quinton Flynn (English voice of Axel/Lea in the Kingdom Hearts series) was almost part of this films cast. But eventually had to step down due to being too busy with attending various events and voice-over work.
"The Road to Kingdom Hearts III" was initially supposed to be a simple recap of events that had happened since the announcement of Kingdom Hearts III in 2013, with a bit of narrative thrown in. But then a bit of drama unfolded during its pre-production in early July 2018, which resulted in a major change in the production team and more cast members being brought in.