@DamianR1352 Usually if there are drastic changes like this, then it's down to licensing or rights issues.

Considering that you have the Dr. Seuss estate and the cartoon special might be connected to Warner Bros. somehow (do know that Chuck Jones was involved and WB has rights to a lot of animated content including the MGM stuff from that time).

Assuming the original sprites aren't mockups (not your well done custom), there might be a prototype somewhere...

Fun Fact: The Grinch game for DS was going to be based off the 1966 special, rather than being loosely based off the 2000 live-action movie as seen in the only three screenshots I can find. It is unknown why the game was change during development.

All the sprites are mock-ups (minus the giant hand and the map icon, which are in the game albeit the latter had a different set of green colors and a white outline around it) based off how the Grinch was seen in the screenshots, which he did wore his Santa suit rather than the lederhosen clothes seen in the final game.

Links to the screenshots are below (You'll also find that two of the screenshots are from a level not present in the final game, as well as the game having different graphics and the gameplay was in the top screen, as well as a different game over screen).
https://spong.com/game/screens/11043463/Dr-Seuss-How-The-Grinch-Stole-Christmas-DS-DSi/253534