Yeees, I don't think there's anything she'd sense from Joan. And since Joan's version of God is God for her canon, he's probably fully able to avoid anybody knowing he's around.

And by my way of thinking the only thing Illyria would get off anybody with powers from the Heroesverse is pretty much what you said: this is a slightly-off human. Unless they were radioactiveman or walking around with no heartbeat or something.