Yea, the docs could use some love. As for setting the flipbook though, you could just set them with a select node and manually pick the asset base on the results of state function. could be tedious with multiple characters, but preobably less painful than making arrays of flipbooks:
The anim state function there just has to branches in it to check for IsFalling and velocity, then sets my AnimStates enum accordingly.
I’ve not used it myself, but there’s a free plugin on the marketplace which apprently has 2d anim blueprints similar to the native skeletal mesh system. Might be worth checking out.