Builds
The campaign setting is very diverse, and its also not entirely serious. Character builds that are interesting or outside of convention are welcome and wont seem out of place in the world as long as its not taken too far. Characters who are optimized or overtuned are only somewhat welcome. My goal is casual fun, not "winning" or hardcore rule following, if a character is built in such a way where its overpowered or minmaxed, I'll take it as a challenge and that character may not live too long.
Backstory & Motivation
Backstories really have no limits, the island is home to a wide range of people and there can be virtually any reason that you're there. The only request, is that your character has some reason to be there, and reason enough to stay or come back if you plan on running with that character for a long time. Your backstory can involve the island if you wish, and I can work with you on how your character fits into its history, or your character could have just arrived, which is common as the island is a destination for adventurers.
Alignment
I dont intend on running any evil adventures, though I wont restrict your alignment based purely off of that. If your character is evil and perhaps changing its ways, or stuck there and forced to help somehow, then so be it, but I would ask for you to not make a character that will actively work against the intentions of the adventure or of your party. In general, things go smoothly if the goals and intentions of the characters align well with the goals and intentions of the quest givers.
Party Dynamic
I do this with almost all of my campaigns as its just the easiest way to get going quickly. Your characters should have a reason to be together, they could be old adventuring buddies, they could have gotten wrapped up in the same mess together, or assigned to a team, but in any case, the party should be introduced and not have intentions of splitting up at least until you're ready to switch characters.