The team as protagonists has shown up in about all of ten issues, It's not a lot of material they have to work with for a a comprehensible film so of course it's going to be a loose adaptation.
Despite Hiro Hamada looking pretty dang Asian? I mean I get the Tokyo/San Francisco "San Franstokyo" hybrid complaint if that's what you're hinting at here but that largely falls into the loose adaptation critique. Until we see the finished character designs for the rest of the six calling it white-washed is premature.
As others have said, Sunfire and Silver Samurai are most likely and definitely licensed to FOX respectively.