How can I access a sublayer that has been copied?
I think it should be something like' copiedLayer[copiedSublayer] ' .opacity = 0 (just as an example)
Or is there any way to access a (sublayer) using its (unique?) ID?
The subLayers are stored in an array, and you can target specific ones by referencing their index. Like this:
print copied.subLayerscopied.subLayers.opacity = 0