I'm not starting the game until Monday, so I've had a little longer than usual to give it some thought. The various UU's are so powerful en masse that I don't think there's much difference among the various combinations - circumstances will dictate my ultimate ratio. What's worth keeping in mind is that any combination requires a lot of units to succeed. The key to an early domination win in this game (before cavalry) could well be based on the ability to generate a large enough medieval army. And that, in turn, is only going to happen if you expand enough early to pump out plenty of gold and units prior to samurai code and invention... while keeping up in research, so that you're not facing muskets and cavalry (or riflemen!) by the time your horde gets past your neighbors.
Given the demigod difficulty level, saving gold and keeping abreast in research won't be easy if you don't get the Great Library. As a result, I think contact with all of the unusually large number of civs is essential, as it will allow a great opportunity for tech brokering. I also think at least one war with swords will be required to have enough cities to generate all those units and gold; if we're lucky, it'll be with some of those three mysterious minor civs. One way to encapsulate all this is that the UU half of the game will go only as well as the setup did - there's little chance to bounce back from a slow start with this UU.