Sometimes it's not so much about the funny things alone, more about editing and timing. If you can tie the funnier b-roll in with the editing and music, you have quite the piece going. I've noticed in some edits, there is an element of try-hard that instantly makes it about half as funny, gotta be organic.
I like the idea of having everybody making the same face, during the rail greasing, slowly zoom in on the face in editing, pause, add some text or a comparison picture, maybe an animal making the same face, then cut back to the skiing. But seriously, B-roll can sometimes be just as important as the skiing shots when making a comedic-style edit.
I'd try to split it maybe 60/40 skiing/humor, that way it's not looking like you're trying too hard for that goofy skier kid look, but still getting that vibe you want.
