In order to access the DLC directly on your PS3, you require a Vita. You can't even get to the point where you would see the levels if you don't have a Vita activated on your end. You can also join a friend that has a Vita, and then play the levels as well. In order for you to use the Vita yourself, you would need to use the share account with that profile loaded up, not your main. Also, there is one trophy that you can not get without owning a Vita yourself (playing 5 community levels).
anybody know if the LPB2 cross control pack DLC would be sharable?
So it is shareable, if you have a friend w/ a Vita to join, and aren't bothered to get all the trophies.