1) The game speed decides how quickly villagers age. If it's set on 2 X one hour real time is worth one year in Isola. So, in twelve hours a child of two will grow up to 14. At normal speed it's two hours = one Isola year. Similarly, mothers will nurse for 2 hours (two Isola years) before letting them go (at 2 X speed).
2. It's pure luck if you get a runner.

Although generally villagers will stick to their assigned task, like any normal people they need a break every now and then. For some reason lots of them find doing their laundry is therapeutic!

Thee problem with the doctors getting stuck every now and then is a minor _bug_. There is supposed to be an update coming out some time that will (hopefully) fix these sorts of little problems (some, at any rate).