I wanna start off my saying if I repeat anything anyone has said, I apologize. I skimmed the thread and just wanted to join in, because I love you all so very much <3
So I just wanna throw my two cents in because I am a user of this technique, First thing is that I don't think a n y KT should be allowed in the Bunretsu No jutsu but i'm sure that's already a thing. But I don't believe that the Sharingan would be unable to fully activate. The sharingan takes so little chakra to utilize that users can leave it on their whole life and not give two thoughts about it. The EMS state takes even less. And they're a physical part of the individual, not created by a jutsu or anything of the sort. However I do feel as though techniques from the sharingan would cost more in the bunretsu technique, and or would also be harder to control, or less efficient. i.e Kamui taking longer to absorb, and the inability to fully control amaterasu. During my current fight with Eric I used Amaterasu while split, but I only used it to the extent of igniting Eric with the fire, instead of trying to shape it into a giant black fire dragon of OP rape, I feel like this would be acceptable.
I also feel like Kekkai Genkais should be allowed on smaller scales (such as in my fight with Eric, even though it took a little bit of nerfing I understand the errors of my initial attempt and fixed it properly, at least I think so.) I feel like things like Amaterasu and KGs could be used on smaller scales because I feel like the complexity of techniques is relevant to two things, the first thing being the rank of the technique, and the second thing being the number of affinities controlled at once. KTs would be impossible to use because you're manipulating three different affinities simultaneously which we all know is a difficult task. However, we ALL know that our individual characters literally possess the ability to blast out high rank ninjutsu like bosses. We're all well over Kage level ninja, at least i'd like to think so. So it would really boil down the amount of affinities manipulated and to what extent. Just as Eric pointed out to me in my initial attempt to use my Mokuton in our fight, I over used the technique as I was making pretty large forests, but after nerfing it down to where I hadn't made large forests, but instead simply bud plants to spread pollen. It was agreed upon. I feel as though with the amount of skill our characters possess as Shinobi as well as the skill our Roleplayers possess as tacticians, the ability to use KGs and high level techs (with moderation) shouldn't be much of a damper. But that's just how I feel about it.
As far as the Rinnegan goes I do agree that it can't be used to it's fullest extent, but I also feel as though we could use at least two paths. Rinnegan bearers possess the ability to use multiple of their Paths in unison (as shown in the conflict between Nagato, Bee, Naruto, and Itachi. which we also all know.) I feel as though at least two particular paths should be allowed access too, these paths would of course be chosen by the split, but I also feel as though they could not be used in Unison. Such as in my fight with Eric, I had activated my rinnegan and utilize the Fujutsu Kyuin, but I'm not shinra tensei'ing at the same time or anything ridiculous like that.
As far as the Hachimon go with the Bunretsu, i feel like only up to the third gate could be accessed in this state because of the limited power and all that Jazz.
However I also feel as Bocchiere does, in the manner that I don't think we really need a set of rules for the technique.