The leaves are made so the main part of the leaf and the veins are two pieces withing the leaf object. This is done to allow the full benefit of the procedural shaders to create a more real effect.
It is easy to add more leaves because each leaf is a separate object. The origin point is at the base of the leaf to make it easy to align.
The berries are all one object but can be separated my using "P" after selecting the ones you want to duplicate.
No it is not because all textures are procedural.