Thanks for the answers... DR cold iron will be perfect for thi character.
About the exalted feats... i just let the player keep the feats that doesnt have anything to do with good, like vow of abstinence, chastity, nymph´s kiss, animal friend, intuitve attack and etc...
I added to the list some small feats from master of the wild like plant defiance, plant control, brachiation etc...
he will gain only 8 feats from the vow alone, so i dont need to give him so many options anyway...