Confusing contacts...why?

I think I’ve been following the Manafort drama very closely but it looks like I missed something. Maybe my friends here on DU can point me in the right direction. Here’s the scenario I think is playing out and the questions.
I think Manafort was placed in the Trump Campaign by either Dirapaska (through his buddy Kilimnik) to make sure that Trump was on-board with release of the Russian sanctions and to secure compliance with Russian policies in Crimea and Ukraine. Why Manafort? Because Manafort owed millions to the Russian Oligarch and I suspect he worked for Trump “for free” under orders from that oligarch in an offer he couldn’t refuse.

The questions that I can’t answer are these: Who recommended Manafort to Trump? Or, how in the hell did Manafort ingratiate himself to Trump enough to take over his campaign? And….did Manafort know that Trump was dealing through Cohen for a Trump Tower in Moscow?

To make it even more confusing, look at all the attempts to create “back channels” of communication between Moscow and Trump. There were (as reported) over 100 separate communications between Trump officials and Russian agents or representatives. Why? Why did they need to do this while Manafort was running a Russian operation at the top of the Trump campaign?
The Trump Tower meeting is a mystery also. The Russians already had Manafort on board, why did they need to set up a separate meeting in Trump Tower?

My personal theory is that multiple Russian agencies/oligarchs were playing Trump for different reasons and decided to proceed on multiple fronts to compromise and corrupt the campaign. It appears to be far more DISORGANIZED than a coherent Intelligence agency operation.

Anybody else have a theory on this?