I assume given the new ruling that Proud Hunters works with Beorn, the same is true of Justice Shall Be Done?

It's worded a bit different, but it still appears that the resource pool is the target, not the hero.

Even without the new ruling, it's already been ruled that Beorn's resource pool is separate from Beorn, and is not immune. Here's a thread from 2013:

https://community.fantasyflightgames.com/topic/83282-beorn-and-errand-rider/?hl=%2Bbeorn%2B%2Berrand

When I'd just read the title of this thread, I was imagining a question about whether Beorn was immune to player elimination. I like the mental image of a big-*** bear continuing to tear through enemies without a player controlling him at all…

4 hours ago, sappidus said:

... a big-*** bear continuing to tear through enemies without a player controlling him at all…

Who can truly control a giant bear? You are merely allied with its purposes.