As for Ancajas, he has more than enough reasons why he needed to win this fight because his career will go down if he will get defeated again by Martinez. But I believe that this time he can defeat Martinez and maybe he can go fight with Joshua Franco afterwards to claim the WBA belt.
If Ancajas doesn't get any trouble in gaining the required weight limit, I am somehow confident that he can win this rematch. We will see a different Ancajas since he will be fully conditioned and possibly have enough stamina to box until the 12th round. We have seen the capability of Ancajas to absorb Martinez's punches, so we don't need to worry about that. Besides, I think Martinez will slug it out again and I believe Ancajas will have a counter strategy for that.
That is his biggest challenge because his enemy is also his own self, might be hard to do but he don't have that much choice as he needed overcome his current situation if he doesn't want to climb another division and leave what he started in 115 pounds. And if by fortunate chance Ancajas will have no troubles this time then I believe that there's no barrier anymore that is holding him to defeat Martinez and he will be crowned as IBF champion again.