What are the implications of repeating the Tawaf al-Ifadah and Sa'i without the intention of Ihram, and is that considered Ihram or a voluntary Tawaf?

There are no consequences for you regarding the tawaf and sa'y you performed, thinking they were obligatory, and then it became clear to you that they were not required for the subsequent 'umrah that completed the deficiency in your Hajj. The tawaf is considered a supererogatory act, but sa'y is not legislated to be performed voluntarily independent of a ritual. You must abandon obsessive thoughts (waswasah) in acts of worship due to their negative impact on both religious and worldly matters.