most of them look very similar

Jenny from Todd and the book of pure evil:

Robin from How I met your mother

I'm not a %100 sure on this one as I haven't watched the show since i was 14 or 15 but tawny from even stevens, plus when the show was airing she wasn't an adult so she fits the prototype for the pointed age of the audience, and I feel could have grown to jenny then later robin

I know there's more but I can't think of them now, I will update as a remember. and also their facial expressions seem to be similar. it's like this one type of look gets typed cast.

It's like these 3 characters are the same character at different stages of life. Tawny the middle school one, Jenny the high school one, Robin the adult one. Now all we need to is figure out a college one and an old/middle aged one