LEO and DAN are real release methods on Nike lol. People aren't just creating new names and acronyms. If you look at SNKRS back end, you can find the names for it.
There are currently 3 release methods that I know of;
-LEO (Let Everyone Order), basically you submit payment within 2 minutes and you get put in a PENDING line, and after that 2 minute is up, Nike selects certain users. Think of it as a mini-draw. Less chances/time for bots spamming entries.
-DAN (draw), 10 minute or 30 minute, whatever time-limit to draw system to submit your entry.
-FLOW, basically First Come First Serve (whoever submits payment the fastest), used mostly for bricks and stuff
edit: oh and of course the infamous Exclusive Restricted Access