I agree that the "Crow-billed Drongo" is a Drongo Cuckoo - the photo even shows it eating a hairy caterpillar which are often quoted as a favourite food of cuckoos!
I also think the Indian Cuckoo is not correct - it looks more like a Chrysococcyx species to me, but I'm not sure which (more research needed).
I love the super close-up of the Black Bittern.