Shrek would suffer from a lack deeply memorable, fun, “safe” songs. It’s best song is a somber exploration on self-actualization, and it’s funnest songs are thinly-veiled anthems for equality. Although I like, “The Travel Song.”
Spongebob, as a show, is far more theme-park friendly. But, truly, a resident, variant-production of Wicked would be the most marketable option.
EDIT - Thinking on it, I would low-key love a stripped down Wicked. Small stage. Smaller cast. Deconstruct the scale a bit so the focus is Elphaba and her relationships and make a 90-minute show with no intermission. It could be a major winner.