Now, that all said, I feel that if the Sun God got to have his own DF, surely the Earth and Forest Gods could too, no? I guess the Sea God is a no-go there, due to the weakness to water and all.
Now, the thing is, I have to imagine Imu got his fruit, Devil or Forest God *after* the Void Century. Because if he was like this during that time frame, his fellow kings were very open-minded people indeed!
Anyways, the point is, I feel Imu has either the Forest or Earth God Fruit...and I feel Teach has to have the other one. I'd say Forest for Imu and Earth for Teach. After all, the idea of a vast world of darkness under the earth is a common theme in mythologies of the world.