The art of animation is not so monolithic that Mary Poppins is the only comparable precedent.
Given Alison's background as a cartoonish, or even given FUN HOME's own animated take on Alison's postscript to her graphic novel, this idea has real promise.
Since PERSEPOLIS was adapted and co-directed by the author (Marjane Satrapi) herself, it may not be likely for her exactly to be hired to adapt FUN HOME, but certainly there is precedent for compellingly rich, complex animation for an adult audience. Other films such as WALTZ WITH BASHIR, the output of the legendary Studio Ghibli and Hayao Miyazaki or Sylvain Chomet (TRIPLETS OF BELLEVILLE, THE ILLUSIONIST) would illustrate that there is certainly artistry up to the task of animating Bechdel's world.
Words don't deserve that kind of malarkey. They're innocent, neutral, precise, standing for this, describing that, meaning the other, so if you look after them you can build bridges across incomprehension and chaos. But when they get their corners knocked off, they're no good anymore…I don't think writers are sacred, but words are. They deserve respect. If you get the right ones in the right order, you can nudge the world a little.