Which Router (wireguard) acts as a server for handshake?
Do any of the routers have a public IP address, or an upstream router that can port forward?
Correct, since maybe 7.12??? not sure when but there is no longer a need to do this on the client (for handshake) peer to re-establish connectivity with the Server ( for handshake ) peer.
Question asked and not answered ????Gray=Dynamic?
In that case do either of the two connections provide a PUBLIC IP, to your MT router, OR to an upstream IP router, that you can forward a port on??