Don't use contains("comeandjoin") because then it will check if the sentence contains the world "comeandjoin". You'll have to check it like this:...
Then check if the slot is empty... and if it's not then add an item to it
Those minigames are maybe not compatible with 1.8?
It's not ItemStack(ItemStack, int) but it's new ItemStack(Material material, int integer) ;)...
We are not going to write your whole plugin... We'll help you if you have concrete questions. If we make your plugin or give you the code then you...
Create a custom slime and delete all the pathfinder goals ;)
You need a scoreboard register a scoreboard for every player apart... There is also a tutorial on this in the resource section
Separate names with a comma.