I usually see them with a ground pork/Asian veggie mixture. I dunno how well the pork belly would work, but the rabbit actually sounds interesting... Maybe some ginger, pepper flake, garlic, scallions? Pretty standard stuff
Ginger scallions garlic soy rice wine sesame oil are standard goodies. Rehydrated shitaki mushrooms and water chestnuts for texture. A bit of corn starch to bind. Pork rabbit shrimp and beef all good. Not too fine a grind on the forcemeat. People seem to enjoy this style of pot sticker.
2 cups all-purpose flour
1/2 cup warm water
flour for worksurface
Mix in your mixer or robo coup. Cut and create balls 1 1/2". Then roll out individual balls to 4" round. While doing this you want you out side edge to be half the thickness of the centre so when you finally stuff your dumpling/potstickers the casings are even everywhere.