Remember, it has to not be something that requires the island ship, actually. We got the island ship afterwards. That's actually a sticking point in a few backstories--they have their characters on the island ship without knowing the others (though obviously it's a minor edit). Also, this next bit may seem weird, but it is absolutely crucial for Nissa that the group did not form in service of Taala, at least initially (in other words, it didn't start as "Taala calls you all together and says--'Hey you six. Go do this' "). We came together in previous mission(s), and then Taala rewarded us for service to the kingdom.