The Canon or Nikon off camera cords should work fine. The pin that triggers the flash is the same on all of them. The flash will only work in manual mode. The i40 will work great TTL on the camera. If you are going to be strictly off camera, you might consider Yongnuo. Wireless trigger and flash are less than the i40. This article has a review: http://improvephotography.com/34962/best-flash-for-fuji/
After reading the article, I bought the combo, and it's great. Both for about $130 from Amazon.
Flash: https://amzn.com/B00PGTOX26
Trigger: https://amzn.com/B00KM1QZRY
