As much as it pains me to say this, I wonder if Kobe would have considered the Nets job if approached. He was obviously very close with Kyrie. Their personnel would be perfect for a triangle type offense. I know Kobe loved to teach the game, though I'm not sure if he ever talked about coaching in the NBA.
I do think that this is why Nash ultimately succeeds though. He shares a similar level of basketball IQ and understanding the game and in many ways approached the game in similar ways mentally. Those Suns teams were always just one piece away, plus the obvious issue of Dantoni never being able to get them to play much D.
Butler and Giannis could be terrifying together. As much fun as Luka and Giannis would be to watch, I'd somewhat be more interested in watching how Butler's attitude and defensive approach would rub off on Giannis. Despite being DPOY, I still feel like he's only scratching the surface of what he can be defensively. Putting him with Butler and Spo would be interesting to watch.
Miami really has themselves in a crazy position yet again. They'd done a good job hitting on picks and acquiring and developing young talent. Next offseason, one where Giannis, AD, Kawhi, Paul George, LeBron, Oladipo, Gobert, Adams, and more are free agents, they're going to have Butler, Spo, a good young roster, space so sign two max-guys and a bit leftover. The thought that they could potentially put together 3 out of these 4 (Butler, Giannis, Kawhi, AD) is a bit absurd in terms of defensive potential.
As much as I don't like Riley, I have to give it to the guy. He won five titles as a head coach and he may actually be a better executive. That's sort of wild to even consider.