I agree, I also am concerned about the game being delayed further if English voice over for the Tangled and Big Hero 6 worlds haven't been completed.
I'm not exactly sure how the actor/actress work scheduling works when it comes to the Disney/Disney-Pixar characters hailing from the Disney worlds for KH3 and the previous installments in the franchise (KH2, BBS, DDD), but since the Disney characters only appear in their worlds and don't play a huge part in the KH storyline like Donald, Goofy, Mickey, Maleficent and Pete, usually the actors who provided voice-over work for these characters (the original actors from the films or a sound-alike actor filling in) varies on availability and there work schedule. Sometimes it will be around 4-6 hours, days, maybe 1-2 weeks to do their dialogue for the session, which ranges from:
1. The Number of lines of dialogue spoken from this specific character in the Disney world
2. The party members in Sora's party, the escort characters, Summons and Disney Bosses doing making comments, grunts, shouts, screams during gameplay.
I agree it still surprises me that the only Disney worlds that have either completed or almost completed English voice work from the trailers released so far have been the Hercules, Toy Story, Monster's Inc., and to an extent the Frozen and Pirates of the Caribbean worlds. My guess the reason we haven't been getting English dialogue for the Tangled and Big Hero 6 might have to do with the actors' work schedules and availability. Well, let's wait for next week's trailer to see if we get any English dubbing for these worlds.