Not sure about the intention with bells and lanterns, but all flowers can't be placed on those blocks, and pretty sure that's intentional
I know. The Creepers in the background are to ensure it's not Peaceful.
Ah, okay. Though, that seems like an odd thing to prevent wither spawning. I understand solid blocks, but don't get torches or grass.
Not sure about the intention with bells and lanterns, but all flowers can't be placed on those blocks, and pretty sure that's intentional