Art, especially cartooning, is founded on abstraction. The majority of details are discarded, only a small few remain. What details are or are not included is one of the most fundamental elements of interpreting a cartoon as a piece of art. Russia, as always, is the easiest example here. Look at what details on the clothing are maintained: The crease in the cleavage, the creases along the pelvis leading into the legs. Of all the details on the surface of the clothing, most others are discarded and these make up around three quarters of the total detail that remains.
Significantly, most of the characterization comes from a confluence of many little details, but to list these is to invite some disingenuous radlib to pick one out and say "Oh, so she's sexualized because she is turning her hips? Puritan!" as though that is what I'm saying. Instead I will ask: Why do all of them have large chests for their weight? Why do all of them [except SA, who is ambiguous due to her arm] have narrow waists? It's because these are fucking waifus, meant to be viewed as objects, not as people. It's wild how radlibs struggle to do anything but media criticism and yet suck so fucking much at media criticism.