It's a nice comparison, but I don't think anyone is the Luffy of the NBA. I'd say LeBron with his ridiculous athleticism and one-on-one power is a lot closer to Kaido than he is to Luffy. I'd also compare the previous group of just retired NBA players a lot more to the Marine Admirals than they are to the Yonko. My list:
Akainu: Kobe (doesn't care how much he is hated. It's all about getting the job done)
Aokiji: Duncan (doesn't care about the limelight)
Kizaru: Barkley (kind of goofy)
Garp: Malone (Fought againt Jordan multiple times but was never able to best him)
Sengoku: Stockton (worked with Malone to attempt to beat Jordan)
Kaido: LeBron as stated earlier
Blackbeard: Curry as stated by OP
Shanks: Kawhi because he's still kind of an enigma, and the Spurs most resemble the easy-goingness of the Red Hair Pirates
Big Mom: Shaq (OP had this one nailed. I don't care if he's retired)
Supernovas: Some combination of the Sixers, Timberwolves and Celtics who are attempting to make good on their ridiculous potential. I'd say with the whole 2 year wait thing and everything, the NBA player most resembling Luffy at this point might be Embiid