The property values of a specific product are contained in index/core catalogue2. There, a product has for each property value a field. For example, item_name or item_price. This fields have to linkage to the properties of the corresponding ontology concepts. That means, the field item_name could be the datatype property name of a chair but it is defined. In conclusion, there is no mapping possible.
I propose to have an additional field in catalogue2 or properties to add a tuple (field name in core catalogue2, property name in core properties). Then, we could create a Entity Mapping Service in catalogue-search