Crucible of Worlds and Burgeoning
You guessed right!  (Sorry.)  There are (at least) two reasons this combo doesn't work.

First: "Playing a land" is different than "putting a land card from your hand onto the battlefield."  They're not interchangeable.305.4  This means that the choice you can make for Burgeoning's effect is not changed by Crucible of Worlds.

Second: Crucible of Worlds doesn't affect the separation between the hand and the graveyard.  It simply allows you to take the "play a land" action with cards from an additional zone.  Since Burgeoning uses the phrase "a land card from your hand," the land that you choose cannot be in the graveyard.




  305.4 Effects may also allow players to “put” lands onto the battlefield. This isn’t the same as “playing a land” and doesn’t count as a land played during the current turn.