Surfer didn't really have all that much help if you think about it. I mean yes he was powered up by the Blackbody, but that was after he proved to be able to get to that alternate universe on his own anyway, and actually he never got rid of the Blackbody upgrade.
As for the Unilord being Eternity level, it was established that the Uni Lord WAS that other universe, which means that he was the equivalent of Eternity there.
Well since Supes himself talked about being uncomfortable with the Motherbox upgrade I think his limited feats with it falls more under the category of CIS than PIS, but it's your thread so I'll abide by the stipulation. And I'm not that familiar with the Motherbox's abilities, but if it's as powerful as people act then it would grant 10/10 over pretty much ANY herald level character(and probably a few skyfathers as well).
There we'll have to agree to disagree, because I didn't see ANYTHING Supes did with the MB that really impressed me. All he really did was use a couple of weapons that the MB provided for him, and all they really were was an ultrasonic gun and a sword. The MB isn't even what sent DD to the end of time, it just reprogrammed Waverider's time travel device to do it. Supes was still plenty vulnerable to attack, and he didn't really demonstrate any enhanced stats or healing either. Based on Hunter Prey Supes might net an extra win or two against Surfer, but I still don't see him taking the majority over Norrin.