Quote Originally Posted by Jojomo View Post
If I have Fists of Iron, can I use it multiple times during a flurry?
Normally you cannot, because you can only use Stunning Fist once per round. However, I think there's a feat somewhere that lets you use Stunning Fist multiple times per round. If you had that, then you could do so.

Quote Originally Posted by Jojomo View Post
Do I understand correctly that each advancement of ki strike after the first grants an additional property to a monk's unarmed strikes, so that by 20th level they will be considered a magical, adamantine, alchemical silver, cold iron and lawful weapon?
Yes exactly. Monks are quite good at overcoming damage reduction.