Sorry, pushed for time -- bad habit I know.
SoI = Sons of Iraq/Awakening affiliated Sunni minority types. Def need to be represented.
The Sadrists, contra the mainstream press, are actually quite anti-Iranian. The irony of the USA aiding an Iranian party (ISCI) fight the Sadrists (broadly, religious Shia Iraqi nationalists -- it does get vastly more complicated than that, though) under the banner of anti-Iranian offensives was sadly lost on most. Read Reidar Visser -- he's the academic who knows more about the politics of Southern Iraq than anyone else -- I can't recommend him enough -- plus, he even has a blog, so you've no excuse.