In the case if the published cast is INDEED true, my opinion on it:
Max Charles isn't brazilian (or isn't latino at least)... doesn't look brazilian either but maybe they didn't really find a good brazilian actor? I mean, he got that childish cute kinda face which would suit Luffy but somehow... I don't know yet.
Mackenyu I doubted first as well BUT I saw screenshots of Pacific Rim Uprising he took part in and his looks THERE looked pretty convincing in my opinion and that vibe would suit him as Zoro in my opinion.
Taylor Richardson... I am not too sure about this. A lot of people (me too) hoped for Emily Rudd because she really pulled of that Nami hair style and she's a big fan of the show. Richardson on the other hand I don't have any opinion about it yet.
Marcus Scribner looks... not whimpy enough? I just imagined someone as Usopp who would look like a weakling? Scribners face looks strong and rough and I really hope he will be able to pull it off differently to match Usopps vibe. For now I don't see it. At least he's black.
Had to google Alex Lange in a suit to just get a hinch if he would look good as Sanji who always wears them. It's okay so far? I mean, he looks a bit too much like a typical *handsome* guy from the movies, the good popular american kid (yes I know he is french) but we will see, with a different hair style and facial expressions I guess.
So far, not a 100% convinced, most still for Zoros choice tho. The rest I will see how it will go for now and wait for more information (and if this is actually true)