Thanks for making this list. You might want to add free agent Trevon Duval. With him, a staggering 25 Duke guys played in the NBA last season (not including Ojeleye because he's an SMU alumn...why is he listed here?).
Of those 25 guys, all except four will certainly be back in the NBA next year. The four guys whose NBA future is in doubt: Luol Deng, Jabari Parker, Amile Jefferson and Trevon Duval.
The Lakers bought out Luol Deng halfway through his albatross 2016 contract, and Minnesota gave him a one-year deal for the veteran minimum. He didn't produce much on the court, averaging 7 points per game over 22 games. And if his main role was to provide veteran stability, the chaos in Minnesota (mostly Jimmy Butler's fault) is not a good sign. There's a chance someone else gives him a veteran minimum deal to be a locker-room presence, but at this point it looks like Thibs has finally finished running him into the ground. My guess is Luol Deng's very good NBA career has come to a close.
JasonEvans already covered Jabari Parker: the Wizards will almost certainly turn down his $20M contract option, but someone will give him a contract based on the promise of his bench scoring. Worst case scenario it's a deal like Jahlil Okafor signed with New Orleans, where a team retains a second year option, meaning all the risk is on Jabari. But he's probably in the league next year.
Amile Jefferson worked his way into the NBA, appearing in 12 games for the Magic. He didn't produce much on the court, but he's too good to play in the G-League. Given how hard he's worked to get this far, I imagine he'll find another contract somewhere in the NBA. I'm hoping he can have a breakout moment next year that can lead to a long career as an NBA backup. But at the very least I think he'll appear in at least one NBA game next year.
Finally, there's Trevon Duval, who played three games with the Bucks, got cut, then claimed by Houston off of waivers, before being cut again. He hasn't shown much in the NBA yet, nor has he put up dominant G-league stats. My guess is he spends next year in the G-League trying to prove he's NBA material.
So, by my count that record-breaking 2019 class of NBA Alum will lose two members next season (Deng and Duval) but add three more (Zion Williamson, RJ Barrett and Cameron Reddish), bringing the total number of Duke guys appearing in an NBA game to 26.