Technically, all co-op challenges do require attempts from everybody, it breaks down as follows:
-Own the Spot: Each player must complete/land a trick on the spot, only one player needs to complete the entirety of the spot
-Line: Each player must collect all tokens in a line, only one player needs to complete all goals within the same line.
-Stunt: Each player must slam, the challenge only completes when all goals are accomplished regardless of who does them.
-Session: Each player must trick in the session, collective goals for all who are participating.
As bd9spx581iji said, play them on your own if you want to feel like you truly did everything required, or need more practice. If I'm doing co-op missions, and have to wait for each person to fully complete the goals (especially when getting to the challenges in Market Mile), each challenge could take 20-30 minutes easily. During that time, I'd just be sitting there waiting, moving the controller here or there to prevent an AFK kick.