This is really minor thing to critique, but did you use reference for bunnies? Because they eyes are looking little unrealistic, which make them look like plush toys. Rabbits are prey animals, so they eyes are on side of head, not in front. So when you look them front, eyes don't look round at all. And If head is lightly turned, other eye goes completely out of view. But this front view isn't so "cute," so it may be hard to find reference. And actually, when bunny look at something, they turn they head. But these are really minor detail things.
Here is couple of photos, to demonstrate. Photos are my own, feel free to use any way needed.
Almost straight from the front, you see very little of eyes and they look really narrow, with sharp points at bottom and top (sorry my English, hard to describe forms).
Here, head is only lightly turned and other eye is completely out of view. That's even more prominent with baby bunnies, because they have so fluffy face.
But you have really nice subtle variations in bunnies, which is great and make them look visually interesting and not like copies of each other. And I really like that you included lop bunnies and "normal" eared. Great variety! And really good job on bunnies thick cheeks, they look healthy baby bunnies.