My opinion is that Poppy, Agnes, Rilla, and Chelsea are pretty cute. Rilla is pretty good design wise because her facial features are well proportioned and she is wearing colors that actually look nice together with her body color. Every other gorilla in the game has an awful color scheme when paired with their default outfit.
I guess I'm a bit biased lol, but I have to pick Rosie. I love cats, plus her big eyes, her pink cheeks, and her singing is so cute. I would say Stitches and Flurry are close seconds.
Marshal or Fauna, the choice is difficult... but I think that the latter's smiling face definitely wins the competition for the cutest villager! There are plenty of cute villagers though: Lily, Molly, Merengue, Alice... most of them are Normal villagers.
Dotty is everything to me! She's super simple appearance-wise, and resembles my childhood pet. That's what I love most about her. If she had a real-life licensed plush, I'd buy it on the spot. Ignore her occasional red-eye syndrome for a moment, and just take in how cute she is:
She's totally coming back to be my neighbor in the next game.