Fire Emblem Heroes Cheats for iPhone

If you link your Nintendo Account to the game and then tap on the 'Misc.' tab followed by the 'Account Management' option you will recieve some Platinum Coins for performing this link-up which can then be used to buy in-game bonuses such as Orbs.

Hero Feathers are items that can upgrade any character once they reach level 20. Below are the three methods that you can use to obtain them.
'Greet' Option:
Using the 'Greet' option towards anyone on your friends list tab.
Friends Leader:
Tapping on the main leader of your friends' party while they're visiting at the bottom of your Castle.
Talking
Talk with your Heroes (they will occassionally gift you with more Hero Feathers).

The following features will become unlocked in the Battle menu when you complete the corresponding task.
Arena Duels:
Complete Prologue: Part 3
Event Maps:
Complete Prologue: Part 3
Paralogues:
Complete Prologue: Part 3
Special Maps:
Complete Prologue: Part 3
Training Tower:
Complete Chapter 1: Part 5