"I am afraid it is not this simple. The route you mentioned is for an FAA MEI to teach JAA MEP courses in the USA."
Yes it is!
A JAA PPL holder with 500 hours can complete a CRI(ME) Course see JAR FCL 1.380.
The training you refer to is for the FI rating not CRI and applies to JAA instruction outside a JAA State in accordance with JAR-FCL 1.300