The playsets from 1.0 and 2.0 will not work on playmode 3.0 you will only be able to play in toybox mode, which is a bit like minecraft... Like Skullyton said you will need just the disc of 1.0 and 2,0 ....
Play Set Mode
Playsets that you can buy,
1.0 Pirates of the Caribbean, Monsters University, The Incredibles, Cars, The Lone Ranger, and Toy Story.
2.0 Marvels Guardians of the Galaxy. Spiderman, The Avengers.
3.0 Star Wars Rise Against the Empire, Star wars Twilight of the Republic, Inside Out,
These play sets have their own unique campaign, which can be played with up to two players. However, only characters from a specific franchise can play in their respective play-set (for example, Mr. Incredible can't be used in the Pirates of the Caribbean play set), meaning two figures from the same series are required to play a play-set in split-screen multiplayer. Playing through play set unlocks objects and vehicles that can be used in the Toy Box mode.
Toy Box Mode
Toy Box mode allows players to create their own game in an open-world arena. Players can mix and match everything that is unlocked within each of the play-sets including characters, weapons and gadgets.....
The rest of the figures that don't belong in the playsets can only be played in Toybox mode....
We have the first 2 versions and just got the kids the 3.0, we brought 12 figures 3 playsets and just the 3.0 disc as they do love it, they go back and forwards from the 1.0 and 2.0 so still getting a lot of use from the first one...