I interpreted this to mean that long ago, there were 3 Peverell brothers, each of which created one of the Hallows. Harry is descended from this family. Note that it doesn't say that "Pevererll's sons" will necessarily be the ones to use their devices to defeat Death, only that the devices are theirs.

Why is space colonization considered at all desirable?

Build something you need. What you don't know, you'll learn in the process.

You may have some inferential distance issues here.

Intelligent people are more likely to think on the consequences when deciding to have a child. But there is a prisoner's dilemma type of situation here:

One reason smart people forego reproduction is because they might feel children make them more unhappy overall for at least the first few years (a not unreasonable assumption). Or simply because they are not religious (smart religious people do still have lots of children) As a consequence, in 20 years, the average IQ of that society will fall (bar some policy reversals encouraging eugenic breeding, or advances in genetic engineering), as only the less intelligent breed. Since, all other things equal, smarter people perform better on their jobs, the average quality of services provided in that society (both public and private) goes down. So in the end everyone becomes more unhappy (even though unhappiness of a childless smart person resulting from societal dysgenics may not outweigh the temporary unhappiness from having a child)

2b seems unlikely given Harry's memory of the night matching the official line. Did Dumbledore do a FMC on baby Harry?

Also, remember that for someone with Horcruxes, one can de facto fake one's own death by actually dying and waiting for the resurrection. There's no particular need to assume that he survived that night in the traditional sense of the word.

It's a real disorder If that's what concerns you. But if you're asking "why use that excuse to exclude Harry from public school and give him a time-turner at Hogwarts? Is there a logical progression that definitively gives Harry a reason to have such a disorder?" I had never considered that.

Regarding the ending comments about Godric's Hollow: there was some earlier discussion about the wizarding community's consensus here.

That description of the line of Merlin at the beginning sure sounded 'sacred'.