Kinda hard to say from here, you were there… That clonk on the front Sway Bar Bushing does look suspect though. Sometimes noises can radiate away from the area when you are in the Car and make it difficult to exactly locate… Problem also is those active sway bars are supposed to move a bit.
I have normal suspension on my Car, just lowering springs to keep it simple so little experience. Hoping Smokeyy or others can help more here.
Number 13 didn‘t exist on older BMW‘s - instead there where „Integrallenker“ like on the e39. When they faded, the car made a noise like an old bed (rattling when entering the car, the same as when driving over humps).
Didn‘t read the whole thread - but do you feel something in the steering wheel, like it would snap you, or is it only the clonking sound, you want to get rid of?
If it‘s the latter one, then I believe, that it can be n.13 in the picture, as it‘s the same place, where older BMWs made a noise like that.
If it‘s the first one, then there should be other bushings and arms, which are able to do that mysterious clonk
Think I will just try to film it again with a GoPro it's such a pronounced feeling that I think it's possible to catch it on camera. Otherwise I'm just replacing random parts without any success 
Well, not much left it seems… Trouble here is it is hard to determine what abnormal play is when you have no reference what normal play looks like… So much movement is supposed to be there by design on active rear steering (ARS).
I assume you turned off ASR and there is no clonking sound ?