For me, the way to fix the CoP is:
The load theater becomes both load and load. Audience boards to the left and exits out the right.
Everything is branded from the Tomorrowland Metro Retro Historical Society. Curtain rises to reveal a movie screen that tells a brief history of how walt was involved with the world’s fair and the attraction. The narrator also mentions that the attraction goes from the 1900s to the 1960s during Walt’s life but a bonus ending will be shown revealing a glimpse of the future.
Acts 1-4 play out as close as possible to the world’s fair version with a replicated act 4 from 1964.
What was the unload theater stage becomes the new future ending. The current act 4/entire family set will move here and be updated on a need-be basis.
Whenever the new bonus ending gets updated, the cast hired will read off the set in stone script for acts 1-4 so that their voices are consistent by the time the audience reaches act 5.