Skip as there are little to no differences:
Big Thunder, Small World, Dumbo, Star Tours, Buzz Lightyear, Millenium Falcon, Rise of the Resistance, Jungle Cruise. The queue is different on Mickey and Minnie's Train Ride but if you're ridden it before at HS, it might be worth skipping since it's at the back of the park
Similar but better or with small differences:
Haunted Mansion has the Hatbox Ghost which WDW doesn't have yet.
Pirates of the Caribbean, far superior
Tiki Room since it's the original
Autotopia, if you enjoy it, it's longer and more scenic.
Different and worth it:
All of Fantasyland, save Dumbo
Space Mountain, ride side by side instead of single file
Matterhorn, outdoor WDW Space Mountain
Splash Mountain, assuming you're going before it closes
Mr. Lincoln
The trains
Everything in California Adventure except The Little Mermaid