1. yes, until such beings are manifestly apparent to all but solitary faithful viewers, atheists will discount them. Pretty much the same way you would discredit Mohammed and his visitations.
2. No one can win this argument. if the universe can't just BE, then how come your god can just be? Ie. you will challenge how was the universe and life created and I will say well then, how was God created? I will accept that the universe just IS and you will accept that God just is.
3. I can live with this definition.