Your FAA Inquiry
Hi Dam:
I am qualified to tell you that you would not qualify for a reduction in hours for the dispatcher course. You may at some of the schools in the U.S. but at the one's that stay with the requirements of FAR Par 65 you would not qualify.
Load Planning is not in the equation.
You cannot take any FAA test outside of the U.S. as the FAA must have the ability to review the testing process.
You can attend a full 200 hours course in the U.S. and receive your certificate as long as you complete the course in the U.S. and take all of your test here.
Good Luck