Is it possible to have more then one VPN with a dynamic IP address at the remote end, if so, how does the inbound RouteFinder tell which VPN configuration to use?

Yes, multiple remote sites can have a dynamic IP address. You can have up to 4 remote sites using dynamic IPs. All the remote sites are also required to a have unique private subnet. The unique private subnet at each remote location is how the central inbound RouteFinder tells which remote VPN is coming in.