okay, based on the responses in that thread, I think it's safe to say that KCM Naruto handily wins the first scenario.
Kidgamer brought up the point that each clone is capable of firing off a guided KCM fuuton rasenshuriken. He elaborated on that point and showed that Danzou's baku-enhanced fuuton blew open sasuke's V3 susanoo and therefore since FRS is a more powerful fuuton it would at least do that much damage. Therefore since Sasuke's V4 is only a level above a V3, it would not be able to withstand multiple FRS. Unorthadox brought up kirin busting a V2/V3 and I have a thread that conclusively shows FRS is not far away from the power of kirin:
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as it shows FRS is a mountain buster as well.
The thing that really seals the fate of EMS Sasuke based on that versus thread discussion is that the pro-sasuke team does not have an answer for Sasuke fighting multiple opponents at the same time. Sure they show how sasuke can deal with a clone, in that the clone wouldn't be able to dodge amaterasu or possibly not even an enton arrow, but they neglect to take into account what the original and the rest of the clones are doing while sasuke is focusing his eyesight on a clone or trying to nail it with an arrow. If Sasuke tries to hit a clone with an attack that leaves him wide open to attacks from the original and all the other clones, and we've seen that just one of KCM Naruto's clones alone can throw a guided FRS or a bijuudama rasengan. So sasuke's susanoo might take down a clone, however in the process he's going to get a dozen FRS/bijuudama rasengans hitting his susanoo as a tradeoff, and that's something Sasuke's V4 susanoo simply can't withstand.
Therefore KCM NAruto handily defeats EMS Sasuke in the first scenario.
The second scenario definitely hasn't been discussed, and I think it is one that's debatable as Naruto combining his KCM with SM to form Kyuubi senjutsu mode would grant him a serious powerup.