Creating editable array of instanced meshes

I want to create a procedurally generated wall, that will randomly choose between pink or yellow segmentv(instanced static meshes). I have two variables: floors and segments. Designer can manually adjust hight and lenght of the wall.

Now I want to create an array of this meshes, that will be editable in details pannel, so that designer can mannualy replace one segment to something else. For example he can choose to replace one of the pink segments for a blu segment.

How should I go about it? I created an array, but it doesn’t have anything in it.

Here is my Pastebin: Creating editable array of instanced meshes > | PasteBin For Unreal Engine 4