Of course u can add them all.You will get a free bonus if u add some crew members using thier I.D by just typing.I think the first new player will recieve x5 riceball and x2 passports while the 10 player added will recieve x5 riceball and x2lucky cat coins.I think there is still one bonus 100 new players.If u don't know what i'm talking about u can read various info and how to invite more players in anouncement of admin where it says "Save Big,Invite More".i"I hope this helps