1 - I imagine you only need to plug it into the Bent Normal node, like the Landscape Grass node, which doesn’t plug directly into the final material output like all the other material stuff.
2 - You will still need to plug your Tangent Space Normal into the normal slot, same as usual.
3 - I’m gonna look through the Robo Recall content now to see if it’s in there.
I can’t actually see Painter mentioned in that documentation, are you referring to some other docs?