Ok, I still don't really see how you think they are that visually similar apart from the typical evil smile and half-closed eyes. The red queen and Ursula both have chubby chins, but that's about the only thing those two have in common.
Well, I am not an artist; also I was talking about impression, of course was not comparing these faces mathematically. Plus this is very much offtopic, and I already wonder if I made a mistake posting this.
But if I am to explain further, these pairs of villains have similar "image" to me in general. First their facial shapes, eyes and mouths look similar. Then their posture and common facial expression too, which is imo an integral part of a character in cartoon (e.g. the Disney "princesses" also seem to very similar set of expressions at least lately).
One mistake I made is comparing Jaffar and Cruella, their facial shape seemed quite similar on the given screenshot because of the Jaffar's smile, increasing the effect, but on screenshots made in different scene one can see that Jaffar has of course got much longer face when he's not smiling (looking at Jafar from other pics made me think they drew him from a camel... maybe it's a real fact...). But on that particular pair of screenshots they look like some kind of spiritual twins to me. Difference in noses, for example, is less important in this context imo, because they blend into rest of an image.
The "frozen"'s male characters posted there look just too much same to me, although of course I realize they have different "weight" to their faces, and different hairstyle, but... don't know how to explain better... imagining overlaying them on each other I see practically same face. It's like they made a "typical good guy" face, then stretched it to create a second character.
Maybe I need to watch these two in action where their expressions change according to situation to unsee this.
What would you consider a good example of clearly different character designs?
Erm... well, the sketches from the "Frozen" posted on the same blog. The first pair is kind of crazy, and frankly I could not believe it was drawn by Disney artists. Guess this is a stereotype in action too... but of course they are all real people with their personal art styles. Second pair seems closer to Disney style, and it's not only that they maybe look differently by face (
maybe, as it's not easy for me to tell by the sketch), but also their style and expression are different, imho this all integrates in a character's "image" in cartoon.