The cane is worth it. It has a very high controll ability that only fails against the toughest bosses and their hold resists and the more enemies you hold, the better is the heal. You can manage without, but having it, will make everything that bit easier.
Same for the shard... It isn't such a lifesaver as the cane, but the two shard copies you summon are tougher than your average security redshirt and can draw focus fire away from you.
You don't have to play the entire Feature Series, just the final episodes to pick up the Bonus rewards.