O2 Sensor + Manifold switching flap

[Olive]

I need your help concerning a problem of lambda sensors.
I plugged a DIS diagnostic system and understood my problem of "engine light" :

I have 3 problems :
- DME - 0C DME : Oxygen Sensor before cat for Cyl 4-6
- DME - 28 DME : Oxygen Sensor after cat for Cyl 4-6
- DME - 1C DME : Intake manifold switching flap



Concerning the 2 first ones, is somebody able to give me the exact references to order ?
On the BMW ETK, I found only one sensor before cat (ref : 11787831624) and 2 after cat (ref 11787832035 + ref 11781405324). Problem : I can not find which ones are linked to the cylinders 4-6.
So : For cylinder 4-6, could you tell me what are the both exacts references of sensor ? Due to the price, I need to be 100% sure before ordering. 


Concerning the third line, I do not understand well why I have this problem. What is the piece to check ?
I looked the device who turning the flap (ref 7511383) but did not found any trouble with it.
Any idea for this line ?

Thanks for your help