Here's my question. You went with Brawler fighter Monk, why? I mean Brawler is a hybrid of both fighter and monk. You should have gone with either Brawler or Monk all four levels. Your fighting abilities would have been stronger overall. RP wise you could have still been as you say a brawler in the streets learning to be a better person or whatever. Fun fact Bruce Lee before he became famous did back alley brawls for money.
Warpriest in this case would be the better of the three suggested of Cleric, Oracle or Warpriest. The Divine weapon ability you can choose it to be your unarmed strikes or a monk weapon. Any weapon with Monk in it's description allows you to flurry. The spell selection is pretty decent. Shield of Faith is deflection so no need for a ring of protection. At first another two to AC. Bless for the buff.
Last thing. I am curious as to what the other players are playing.