Add path operation to multiple shape layers
Use Expression Slider Controls to drive multiple Shape Layer Wiggle Path Values.

Here is an example of driving Size and Detail values of the Wiggle Path Property on 6 Shape Layers with 2 created Slider Controls on a seperate Null Layer:



Note: To save time, it's a good idea to create one shape layer first, set it up as described below and duplicate it afterwards to maintain the expression links.




Create a Shape Layer and a Null Object
Add Wiggle Path Property to the Shape Layer 
Add a Slider Control to the Null for every value you need for animation (size, speed, correlation ...) and name it like these for a better organization
Select the Null and go to Effect > Expression Control > Slider Control
Open up the properties of the both layers by clicking on the small arrow  >  right beside the layer's name to see the values of the Wiggle Path and the newly created slider control at the same time
Holding down Alt while clicking on the stop watch of a Wiggle Path Value like the Size or Detail, this automatically will insert an expression
Use the expression pick whip and drag it onto the predefined Slider Control of the Null before to link/parent it, for e.g. the Size of Wiggle Paths, this should create something like: thisComp.layer("Name of the Null").effect("Size")("Name of Slider Control")
Repeat the process of parenting the Wiggle Path Values to the Sliders as long as all needed values are parented to slider controls correctly 
If you duplicate the Shape Layer with CTRL+D now, all expressions will retained for the duplicated layers