I highly doubt there would be anything resembling ancestor worship any were outside of Far Harad and Rhun.In Eriador specifically, I would envision the reverence of ancestors being the closest thing to religion. And I use the word reverence very intentionally instead of worship. I could see a small farmstead consisting of a few families perhaps with an old sword above the hearth that belonged to a distant ancestor. And perhaps they tell stories of that ancestor’s deeds to their children to instil moral lessons such as loyalty, determination,kindness, etc.