Compared to the rest of the cast, Ella is indeed "slim", but not compared to the girls in ToN, which was what the OP was referring to. Judy is indeed de facto slim, but not an equivalent to the body types of Alia/Emily. FWIW, I don't really feel like there's an actual lack of variety, I was simply arguing that, while this one argument could be entertained, the claim that those characters could pass as related because of a body type similarity that the OP made is silly. Are Henry and Canmore related, too? They share body types and dick size, after all.
I'm personally okay with the level of variance in TGO.