A few quick notes about instancing support in HtoA:

• For instancing, use the Instance object with fast point instancing. HtoA doesn’t support full point instancing.
• You can assign material to instances with the shop_materialpath string attribute on the instance points.
• Fast point instancing supports per-instance user data and instance OBJ property overrides.
• Light instancing is not supported [yet]. Actually, Arnold itself doesn’t support light instances, but what plugins like MtoA and SItoA do is translate the light instances into duplicates of the light for Arnold.
• Procedurals (both DSO and ASS) can be instanced.