Okay, so I looked on deviantart and pinterest for Ninjago fanart and wow, a lot of it’s really well done. I feel like that kind of stuff gives me an excellent idea of live-action ninja. I saved some of the things I found on my pinterest, under the same username. 
I think that a live-action Ninjago movie should keep the looks from the pre-SoG, though. I don’t know how easy it would be to get actors that fit the ninja’s descriptions, but I’m not expecting a live-action movie anytime soon, maybe years later.
I also found a link on these very well done Ninjago posters on the same website as this! It’s also ttv so I don’t think it would count as advertising: 
Ninjago Season Posters