Pretty much what nagaoka said: I think it's stretching the definition of racism. Unless there's an implication that one race is superior to another (which there might well be in these examples, depending on context), it's not properly racism, just stereotyping of a group. Which can still be offensive or patronizing, obviously.
I don't see what any of that has to do with whether naive portrayals of people of other ethnicities in a way that emphasizes differences from typical Caucasian features is inherently racist, particularly when made by artists and for audiences who weren't used to seeing such faces in real life. Comic book art is to a large extent about exaggeration, and the baseline is always going to be the everyday.
Rather than continue this discussion in the abstract, I think it would be more interesting to do a series looking at how comics have depicted Africa and Africans over the years. Maybe that would make it more clear which stereotypes are innocuous (keeping in mind that comics rely heavily on stereotypes in general), which are embarrassing or politically incorrect, and which are out-and-out racist.