The Web of Challenges at first glance seems difficult. It maybe was while you were playing the game and got side tracked with them, but this is not the case when you play them separate. After beating the game you will have unlocked all possible challenges (you do not have to accept/attempt them at time they are offered in story).
Use your powers for combos, it makes it extremely easy. You will have to try a few times to do the orb challenges. The only challenges that might frustrate you are the free-fall challenges which almost take memorization (somewhat). Otherwise, the challenges are not difficult and most take under a couple of minutes to complete. Doing all of them from scratch should take you less than 2 hours.