Ghostbuster

Why would you send a ghostbuster to the island. Does this mean they
know about Jacob on the outside?  And if they do, are they trying to
get rid of him or do they have another purpose in mind?

"A headcase, ghostbuster, anthrapologist and a drunk (pilot)"

It seems an odd combination of people to drop on an island with one
bodyguard, especially when they know about hostiles on the island.