This node will get elements from a Link Instance given the instance object and a Category. It also reports a ‘coordinate transform’ for the Link Instance itself.
You also have the option to simply pick the linked instance with the “Select Model Element” node:
Dynamo Nodes 
How can we get the Origin Point X,Y,Z from the transforms without splitting the list or using list.chop? This will allow the placement of new families at these origin points.