Haven't had one of these for awhile. This thread is for questions or comments that you've felt silly about not knowing/understanding. Let's try to exchange info that seems obvious, knowing that due to the illusion of transparency it really isn't so obvious!
I first wanted to comment on 5, because I had previously read that having children reduces happiness. Interestingly, when searching a link (because I couldn't remember where I had read it), I found this source (http://www.demogr.mpg.de/papers/working/wp-2012-013.pdf) that corrobates your specific expectation: children lead to higher happiness for older, better educated parents.
Having children is an example where two methodologies in happiness research dramatically diverge. One method is asking people in the moment how happy they are; the other is asking how they happy they generally feel about their lives. The first method finds that people really hate child care and is probably what you remembered.