Really, it's hard to picture a data format that's pretty much the standard for the era ever become totally unreadable, so long as the data is intact.
O rly? Know that ubiquitous Save symbol? How many under 18 have ever seen a real floppy disk? That aside, I second the M-Disc in a player with autoplay; the disc will survive, a player built to last may also survive.
The current size of the human head is limited by the pelvic size of women
This is incorrect, the reason human babies aren't more developed at birth is because the energy required to continue development is larger than the energy the mother's body can produce. Unfortunately, my google-fu seems to be faulty; I can't find the BBC documentary where this was shown...
The hardest part of climbing the ladder of success is getting through the crowd at the bottom.