so i tested stuff with logbook:
Adding RFK, Aether, ect to an avatar, saving in logbook, rerecruiting it
it will add those skils to your permanent pool
Adding enemy only skills: Dragonskin, Luna+, hawkeye, RFG
They are not added to your skill pool no matter what you try
hacked in passable skills (Aether, RFK, Conquest) CAN be passed to children.