Eric is right in that a legal marriage was never a biblical requirement, that came centuries later.
It isn't a legal requirement anymore today either, a common law marriage is accepted in most western nations, but for inheritance and tax purposes, a legal marriage is still often preferred.
The WT uses the paying Caesar's things back to Caesar as a reason to be legally married but thats taking the verse completely out of context, as it refers to taxation, not marriage. The WT is also REALLY good at only applying this to their r and f but never themselves as an organisation.
In fairness to Eric, he has exposed the WT and Christendom lies re women and their role in first century Christianity, he acknowledges clearly that the scriptures speak of women judges, prophets, apostles, teachers and healers.
Whether Eric and Wendy are legally married or not is nobody's business but their own, same goes for anyone else.