Hinako is original, I mean you don't have to be fat to practice Sumo Wrestling. Obviously the sport rewards those who are fat, because it's harder to push them out. But in a fight, the sumo fighting style can work against people with normal weight. So IMO Hinako not been fat fits well in KOF, since most of her opponent aren't fat and huge. So she is not that out of picture as martial artist, about her design, well that is another subject. I say it's odd, but that adds and makes her more interesting visually. Is hard to imagine a Blond European girl doing Sumo Moves, I wouldn't have never thought of that, so I give SNKP credit for creativity.
Malin has never been on my liking list, I don't like her voice and she can be annoying. But her design is not bad, is just her voice and the gameplay she has. I think SNKP tried to pull out a character that used Yoyo's like Bridget from GG, but it didn't end up well IMO. Her fight style doesn't really work that well either, but I can see the potential in her if they change a little her fight style.
Choi and Chang... I rather not talk about those 2, I just don't like them. =/