Facebook Audience Network related questions

I decided to integrate FAN in my application, my app is live on Google Play store but I haven't published yet the version that shows ads

1- Do I get to submit it to get reviewed by Facebook or do I have to publish the version that shows ads first?

2- I'm using a bottom banner ad and I show it in different activities of my same application, is this against roles or acceptable?

3- How frequently should I call adView.loadAd()?

Knowing that in my case I call it inside onCreate(...) of the activities that show the same ad unit. which means that when the user navigate from one activity to the other it will recall adView.loadAd() on the same ad unit, and it could be in a small amount of time, could be few seconds.

4- Is there an amount of time where the ad should be visible to the user before it's considered / counted as an impression?

5- Does Facebook pay me based on impressions or clicks or both?

6- Does Interstitial ad impression earns more than banner ad impression (In case of all other conditions / factors are the same, as the country where the ad appears).

Thank you and if you have an advice to help me more it would be really appreciated.

from Facebook Audience Network related questions