How well is instancing in Blender handled in this? I saw it does work, but I can't tell if there's a performance boost or not like would normally be the case.
In general it just treats the instances as an additional mesh to render, so performance would be similar with the same number of polygons between an instanced model and non-instanced model.
Prefab will share texture memory between instances, so that will help GPU memory. In general, what is your concern? CPU memory? GPU memory? Performance?
I see - it won't change that. If we need to draw a poly, there are not many ways to improve that, except by batching. In this case batching for a particular model is most dependent on texture changes, so if you use a texture atlas / single texture for a model, it will be able to batch well.
