…The Here Humans! Action states: “If this is a two player game, only take one of that player’s Human cards.” (Human is singular)
A: I checked with Andy on this, and he says that Here Humans! should be absolutely able to steal an opponent’s Humans In Black. Though it uses “Human” in singular, you can’t really separate them as a group, and they would be just as susceptible as other Humans to whatever you’re using for Human-attractant (some sort of audible call? “Hay-bay-bee!” Or maybe a scent-based attractant: cinnamon rolls, or those candied almonds they sell at the mall? Or maybe it’s a visual thing: a billboard for some irresistible deal or “free money!”)
In fact, they count as Humans for anything referencing them, even The Humans Are Revolting, for example. The only real difference is that they’re not Creepers, and have the special power to nullify the Creeper-aspect of other Humans.