Yes I think that the material I cited has lots of good stuff in it, but it would need to be reworded for use with a young child. I think you are right especially about PD5 and the wise/honor/just issue being dangerously Platonic-sounding for someone who doesn't yet understand that those terms are relative/subjective rather than being absolute.
It might be that one of more of the Vatican Sayings is more easily employable. I've always thought that some kind of wording of 47 might be good:
47. I have anticipated thee, Fortune, and I have closed off every one of your devious entrances. And we will not give ourselves up as captives, to thee or to any other circumstance; but when it is time for us to go, spitting contempt on life and on those who cling to it maundering, we will leave from life singing aloud a glorious triumph-song on how nicely we lived.
But I think depending on how long you feel like is workable, pretty much anything needs to be reworded for simplification.