If you are invited to wedding of your foreigner friend?

Hello!!!My friends!

Could you listen to my worries?
Next year I would go to a wedding of my foreigner friend.
She has been my best friend since I went to Guam to study. 
I really want to celebrate her wedding and surprise her !
But this is the first time to go abroad. I am worried(＠_＠;)
I have to prepare passport, "Aloha dress"and "Mumu"
what is called party dress in Guam.
I waver wedding present.
She likes blue and I want to give Japanese traditional items
and useful for their new life. 

Would you give me advice about wedding presents?