Well, if they are opposed to evil, then they are more likely than not Good. Though unfortunately the level 10 aspect of your ki pool only makes your attacks lawful aligned, which is of little help against most evil outsiders, an Amulet of Mighty Fists with Holy should alleviate that.
Diamond Mind, to help negate the fear tactics popular among fiends seeking to terrorize the masses, seems valuable. Elemental Fury isn't very good, since fiends have elemental resistances all over the place.
Use a temple sword, you can flurry of blows with it and it can be enchanted or made of a specific materials to bypass DR. You do great damage. Unchained monk, unlike normal monk gives you the bonuses from high strength and power attack while 2 handing.
You could always take pummeling strike at later levels to get through DR with your fists when fighting outsiders
Always take flying kick as your level 5 style strike, going from 1 attack because you needed to move to 3 because you have free movement as part of a full attack makes a world of difference.
Since the adventure path you are in is a mythic one you have a unique opportunity. Instead of going the typical STR based monk go for a finesse monk. Priorities your stats in the order of DEX, WIS, CON, INT, STR, CHA with CHA being your dump stat. STR and INT can be left at 10. Take weapon finesse and for your first mythic feat take mythic weapon finesse. This means you only high scores in two stats, and medium in one. Since these stats also give you AC and saving throws your defenses are going to be very good. Mythic weapon finesse is going to allow you to keep a reasonable damage despite having a low STR.
Your first Ki power should be Barkskin. Take Crane style to further increase your AC while minimizing your penalty to hit. By about 9th level your defenses is probably going to make your GM cry.
If you really want to push it to the limit play a Vanara.