For some reason some mobs don’t spawn how they are support to in certain biomes. The modmaker of the mobs mod told me it must be because of the biomes themselves not having the compatibility. Can this be implemented? with the Bop world gen?

https://github.com/BobMowzie/MowziesMobs/issues/136

Lost Cities doesn't do biomes. It is just worldgen so that can't be the cause.