1) In AdMob there is mediation that you can do to exclude ads of adult nature and many other categories. There's nothing for "rating", would be smart if Google did this. Chartboost doesn't do this either, but lets you exclude apps rated 17+. When using AdMob we took out Adult, fitness/health, religious, and occult. Chartboost only advertises games so it's no longer a concern for us.
2) 15-30 seconds is even fine for refresh. I don't think a user needs to see a banner for long, but 15 sec is a bit fast. 60 is plenty time, but it is decreasing your impression count. The more impressions, the better the chance that you'll display an ad of interest to your users.
3) Publish in all unless you use some sort of encryption that is illegal in certain countries (I wouldn't worry about this) or if your app somehow violates a country's laws (I wouldn't worry about this much either). I'm not a lawyer and this is not legal advice.
We have an LLC for our US-based company. Many devs publish under their own name. I'm not sure why that would be different in the UK. I know devs in many different countries using their own name. Regarding sharing your address... this sucks, complain to Google. They need a better way to handle it. Our office is our home... our home address is now public. Am I concerned? No. Am I annoyed? Yes!
Hope this info helps!