So the issue i'm having is that the delightful dirt only spawns 1 passive animal the drygmy from ars, Is there a way to fix this to allow ALL passive animals to spawn? or does this have to do with the biome and (or) can I make it so all can spawn even if its biome restricted

I had the same problem, but it was because I didn't have light level 10+ for all the blocks

What biome is it in? because it is indeed based on the biomes spawn tables.