Which of these are more likely for Wrestlemania 27?

Well Undertaker vs Wade Barrett with the streak on the line is pretty much penciled in, but I can't see Ezekiel Jackson in a world title match this soon, considering its Wrestlemania the biggest show of the year. So out of your options number 1 seems more likely because Barrett could send his "enforcer" Jackson over to take care of the Undertaker while he can try to take the World Title off from Edge. Either way its a worst case scenario for both.