Cloth diapers(USA)="Terry towelling Nappies"(UK) or "Proper nappies" to the older generation.
Thanks to the BBC there is an inhibition against using trade names in English English , so Pampers etc. are often called "Disposable Nappies"
An alternative explanation for Natty Dread came from a British Jamaican I knew, and that is that is is a Kingston pronunciation of "Knotty", meaning tangled.
Their way of turning an "o" into an "a" also occurs in the , highly offensive,Jamaican phrase used to describe a gay man "batty boy". (I'm sure you can work it out!)
Is there a relationship between "nappy hair" and the raised Nap on cloth such as that used to cover Pool tables?
I did hear a funny story about an African American who visited some people I know in Nigeria, proudly wearing his corn-row hairstyle. He was puzzed by the amusement of his hosts, until it was explained that tight plaits that stick out were only worn by baby girls in that part of the world.
Cheers
Dave