The mod is, primarily, using most of Lloyd's battle and cutscene files, with Nimoy's lines being used in a patchwork fashion to fill in gaps (ex. victory quotes, some defeat, etc.) The combat dialogue has been completely replaced, with 2 minor lines being silenced entirely.
Not all of Hauer's dialogue has been replaced, and cannot realistically be done, unless someone knows a Christopher Lloyd impressionist or can commission the actor directly to provide the missing dialogue.
Please leave feedback on how you feel the "DARKNESS REIGNS" line is used during the final fight. Again, without a commission or accurate impression, this replacement pack is about as finished as it can be. Please enjoy.
Unzip the folder contents to "KINGDOM HEARTS III/content/paks/~mods" wherever you installed the game.
Delete the pak file. Easy.