One of the things HOME ALONE is famous for is its wonderful, charming, and heartful music score composed by the great John Williams, but he wasn't the original choice: the job was intended for Bruce Broughton, though he ended up scoring THE RESCUERS DOWN UNDER instead (both released in 1990, and both including John Candy in a role).
I've observed that more often than not, Bruce Broughton's scoring style has a rather distinct sound to it: a lot of French horns, and other really brassy instruments (THE RESCUERS DOWN UNDER and HOMEWARD BOUND are a couple of examples), and I can't imagine such a score really befitting HOME ALONE . . . however, Bruce also scored HONEY, I BLEW UP THE KID, and when I listen to that score, I can actually imagine a score like that working well enough for HOME ALONE had fate worked out differently.
Still, John Williams ended up being the perfect choice, even if they thought he wouldn't be able to pull off a score for a family comedy.