The Crowd of agents is an array of regular characters, but rander than having a Skeletal Mesh, theres only 1 Instanced static mesh component that Updates the transform of each instance to the transform of their corresponding character actor, the material shader for the instances uses the material functions included in the plugin.
As for the second question, the way animation is selected is by simply scrolling the UV coordinates along the y axis, it is mostly based off of Houdini’s version of the same technique explained here: