By the book (PHB p.190):
You can also interact with one object or feature of the environment for free, during either your move or your action. For example, you could open a door during your move as you stride toward a foe, or you could draw your weapon as part of the same action you use to attack.
And from the Jarlaxle stats block from W:DH (p. 206):
Quick Step: Jarlaxle moves up to his speed without provoking opportunity attacks.
The question is: Can Jarlaxle take free action in his legendary action? I'm thinking something like: one of his drow assistants opens his portable hole over the gold as an action (swallowing it), the other drow closes the hole (as an action) and Jarlaxle uses his legendary action to take the folded hole and leaves using his legendary action at the end of the last drow turn. Is it possible?