Not sure re: "parental rights" for nonrev discounts. I'd just call each location directly and ask.
I'd be looking into hotel credit cards.
Chase Marriott offers 1 free nt certificate+points.
Starwood (Marriott eventually) has great point deals.
Amex cards offer auto upgrade to gold status so you get lots of perks.
Call Accor hotels and ask if they extend airline discounts for Delta parents (may have to email). I am guessing you'll have to have your "child" access for you via DLnet but I don't know for sure.
See PM for JFK advice...