I'm unsure if the breeding for rabbits is disabled intentionally for Wild SMP and if so then understandable. Rabbit's are very niche mob to want as their drops are almost useless compared to other mob drops, but they do have a use for potions. Finding rabbits naturally in the wild is a very tedious task, and when you do find rabbits the % chance for the feet to drop is low, only 10% with 3% incremental increases per looting level up to a maximum chance of 19% with Looting III per the wiki. In my search for rabbits on the server, I've only ever found and killed 16 and of those 16 only 4 dropped their feet. Looting does not effect the quantity of feet dropped, it only increases the chance of dropping and if you want a full shulker of leaping potions you would need 9 rabbits feet. Having rabbit breeding disabled makes farming them more tedious than farming pufferfish or scute from turtles. I would not suggest adding a rabbit spawner to the spawner crates unless this was already planned, as it would only lower the % chances for other better mob spawners unless you were to replace another spawner already in the crate. Realistically, only the Leaping II potion is viable to make as this makes you jump 2 blocks high, so this would really only be beneficial to those without /fly to use while building or mining, and those who like to spice up their parkour areas, as well as those who like to have a readily available stock of all potions to use/sell. Thank you for coming to my TED talk.