So having played this a few times now I still can't see any way of getting an alpha player within the game far to many moving parts.
However, there is a contingent in my local gaming group that take the attitude that co-op games = 'someone is playing the game whilst everyone else is just doing what they say' due to some bad games of Pandemic. Does anyone have any suggestions on how to sell them on the game to help overcome the alpha player blues?
For me, a lot of the focus is usually on the simultaneous play. I find that in games where each player has a turn and everyone else is sitting there waiting for that player to make their decisions, there are more opportunities for an impatient alpha player to interject. Granted, even with simultaneous play, you'll still have some people who make their decisions quickly and some who like to mull it over for a while; but because the spirits are shaped so differently and after the first few turns, you can't count on knowing what powers another spirit is holding, it's much more difficult for a player to know the "right thing" for another player to do.
I've played Spirit Island with several players who flat out just sat there until someone made a suggestion. I was helping them a bit early, explaining options and such, and then I realized I was starting to Alpha them so I stopped. One player took 20 minutes to take a turn. Eventually the other player told them what to do.
It was infuriating. They just sat there looking at their ards like they were deep in thought, but apparently they were just waiting for someone to tell them what to do. Gah, so incredibly annoying.
I've seen a few players who get overwhelmed, too. I usually ask those players to identify what they think is the biggest threat near them and then have them try to come up with a way to deal with it. There are a lot of choices to make in this game; giving players something to focus on can help to keep it from getting overwhelming without telling them what to do too much.
To answer @Demiher0, I concur with @grysqrl's response: simultaneous play.
All of the alpha-player issues I've ever seen (including those mentioned in this thread) happen when people *don't* play simultaneously, which lets someone else reach over the table and tell them what to do. As long as all of the players are relatively good at picking up games and have interest in being proactive with their characters, it shouldn't be an issue.
I thought it might be the simultaneous play aspects because it would take a better mind than mine to play a spirit and then play someone else's turn as well…
The other way I have played around a known alpha player was to let them pick spirits that change how you have to look at the game to keep them off kilter (Looking at you Oceans Hungry Grasp, Bringers of Dreams and Nightmares)
Anyway shall discuss the simultaneous play aspect with them next boardgame night thanks for the help 
It is the simultaneous play combined with the number of decisions and the hand management which make it almost impossible to alpha-game. Unless somehow you could memorize what power cards each player has, know all the elements on each as well as the element thresholds for major powers and everyone's innate ability and THEN remember exactly what they played and what is still in their hands, you simply don't have a clear idea what the choices other players are making even look like, which is kind of a necessary pre-requisite for being able to suggest one of those choices as better than the others.
This is a truly co-operative game with lots of communication, but in my experience, that communication looks more like "I can take care of this problem, if the rest of you can handle that one," "Who wants to repeat a power this turn?" "Can anyone do 1 damage here? If so, I can finish them off" or "So, do you think it is more usefull for me to remove this blight, or prevent that build?" The closest to alpha gaming you get is "Hey, do you still have that card which lets you give someone else an extra element? If you play that it would let me trigger my innate and give us three fear" and very occasionally "Oooh, it would probably work better if we have the ability you picked take effect before the one I picked because X"
For me, it's most often "Ack!! Don't destroy that town, I was planning to use it for XYZ! Maybe you could do ABC instead?"
We play simultaneously but some suffer from choice paralyzation. Too many things to do and too many options and they ask me what to do. While I love to alpha game, I have to stop my self. Usually, because I am overwhelmed in later turns and don't want to make every decision in the game. I have started to say, like Grysqrl; What can you do this turn, How can that help the Island, You can not do everything, blight might happen, We have placed marker down where we are helping. So do what you can and we will fix the rest later.
Now she is the one done before I am some turns, Thunderspeaker gets nuts deciding where to use innate as fast or slow powers.This is a game where the more you play it the easier it is.
Yeah, I am feeling that I am getting how to play more now that I have played the spirits more than once. Serpent is still my favorite especially when players suddenly just get extra presence on the board because I haven't looked at my elements until the slow phase... Doop de doo.
I also raised it with some people whilst playing at my lfgs and they disagree with the simultaneous play argument. There logic being because there is so much card / board interaction that needs to be discussed that we have to choose how to resolve what card when to prevent player x from drowning a city when player y was going to turn it in to a town/players get the chance to just talk over everyone to say this is what I am doing n you can't stop me.
Yes, you do need to talk about things, absolutely, which breaks the simultaneous thing a bit. But as I said, I don't think that the virtual impossibility of alpha gaming rests on the simultaneous play (that just helps) so much as it does on the complexity of the decision space and the amount of information that those decisions depend upon. It is impossible for anyone to tell other people what choice they should make out of 7 different options if they can't even keep track of what those options are and no one without an idetic memory could possibly keep track of all the cards/elements/thresholds that three other players might have in hand at any time. Each player has their own, essentially solitare engine-building, hand-management game going which no one can really help them with. In that sense it is more like a euro-game than a traditional co-op like Pandemic or Ghost Stories.
Where those solitare games intersect is on the board, and that part *does* play out a bit more like Pandemic, in the sense that which spaces each player focuses on dealing with and in what order is something that needs to be discussed and decided collectively. I guess, if you have a really forceful personality in your group they can try to dictate that side of things to other players (though I have never seen that happen, in a number of very different groups), but the private game mitigates this to a large extent: In Pandemic, you know what other players *can* do, so you can tell them where to go. If someone tries that in Spirit Island, the very easy response is "Sorry, I don't have any powers which let me do that now, I can only do this or this."
More basically, if you think about the reasons *why* people try to alpha-game, by far the most common is surely the desire to win. If you know the game and the puzzle, it can be hard to watch someone make what you know is a much less effective and efficient move than the one you see. But if you don't know what their choices look like, that motivation won't arise in the first place. You know you have imperfect information, so you are more inclined to trust that they know their hand and engine better than you do. And in general, if you are playing at a difficulty level which is sufficiently challenging, there are so many problems on the board, comming up with the most efficient way to win *depends* on that trust and genuine co-operation.
All that said, the way you describe your friends' argument, their concern isn't actually with alpha-gaming, it is more that they all want to be alpha-gamers and are afraid someone else won't listen to them! Saying "I'm doing this, and you can't stop me!" isn't alpha-gaming. It could be an outright refusal to co-operate, which can break the game. But more often, I think, it is an assertion of autonomy in the face of alpha gaming! If no-one else has an incentive to alpha-game then, it follows, that they wouldn't have an incentive to be stubborn and ignore the needs of other players in response. *Everyone* want's to win, everyone wants to have fun, and if you don't have incentives like in Pandemic where one person's desire to win is in conflict with someone else's desire to have fun, my experience is that that conflict simply doesn't arise.
So you get genuine co-operation and de-centralized leadership emerging, with players trusting each other, actually *talking* about pros and cons of choices, and comming to a reasonable collaborative decision. It's really satisfying purely for the social dynamic, even without the fun of the game itself, because it is enjoyable to be a smoothly functioning, cohesive social unit with other people.
Most of my first games were 1-2 players so I didn't really have a prodlem with Alpha-Gamers. But the first time I played with four players the two new players were so overwhelmed with all the moving parts, I ended up directing all of one of the player actions. The reason being because she chose her cards based on which ones' art looked the best and their names.