Upon whom falls the sin of lying to the marriage officiant about not having consummated the marriage with the divorced wife, knowing that it did in fact occur?

The sin of lying falls upon the one who commits it, whether male or female. It is forbidden and considered one of the major sins, and one must hasten to sincere repentance. If the marriage took place without the guardian's permission, it is invalid according to the majority of scholars, unless the husband follows the Hanafi school of thought, in which case it is valid. In any case, the woman is entitled to the specified dowry or the dowry of her peers.