Welcome to FT - AA,
tryinthis.
Our answers may seem all over the board to you, but speaking for myself, I'm really am not sure what you're asking, particularly if you are asking our opinions. But...
Each flyer can have his / her own account, and we can "buy" awards for others with our miles and give them to the child - or to anyone else, for that matter. To remain "alive," the account must have some kind of qualifying activity at least once every three years - not a bad thing to gift some miles annually, so when the child grows to the time s/he can appreciate / make use of them, they've got miles.
For some of us these miles are like crack cocaine, particularly when reinforced with a first class award trip to Europe or Australasia
- I opened an AAdvantage account for my grandniece when she was about three days old. I'll probably buy her some stocks / shares periodically as well.