A bit of a tricky question to answer. Depends on what they plan to catch, and also what rivers they plan to fish.
So many VI flows are small and tight. Today I was out with a 9'6" single hander and felt like I had too much rod with the trees. The longest cast I felt I needed to make was just shy of 50ft, and most of the time 35-40ft was enough to catch the bush on the far side.
If I were headed to get chinook, then I'd want a short and nasty strong 9wt or even a 10wt than likes to huck the grains, but certainly not a 15ft rod unless I was on some really big water, and there's not much of that on the Island. Probably something around 12ft would be better for me.
Other than that, probably a short 7wt spey or switch would do the trick well enough.
But since these guys are likely not to be buying a new outfit or two, I'd be more inclined to match their existing gear to some water which might hold a fish or three, salmon or otherwise.
Hard not to start them off on some well known big-ish water like the Cowie or Stamp, then go from there.