Very good so far 
You need a totally generic pickup BP.
It’s just like this
The mesh is just a static mesh reference, but it’s not set to anything. It’s exposed on spawn
And in the construction script
So to make a sugar cube pickup, you just put the BP in the level and set the mesh to a sugar cube. Or, if you want, you can make the sugar cube a child actor of the main pickup BP ( by right clicking in the content browser ) and set the cube there…
Same thing when you spawn it, because you set that variable to ‘expose on spawn’ it appears in the spawn call, and you can set it from the character.
Tell me if it’s not clear