You make some very good points, but here goes:First off. The Yin part is sealed in Minato, who is sealed by the death reaper..
2nd, no TBB doesn't require yin + yang. We have seen other shinobi using only yin or only yang to create / use ninjutsu. 2nd mizukage is a good example..
EDIT: Also Bee seemed to be very surprised about Narutos rasengan. I doubt it has anything to with yin or yang. Bee would know.. So it has probably nothing to do with yin and yang.
Also Kurama never used a TBB, when he took over Naruto? That one against Oro was just pure chakra I think. And he swallowed it. So it's probably not the same. But inside Naruto, when he fought Kurama to gain control over the chakra, he did try to use a TBB. So that kind of bashes it, doesn't it? I mean Kurama couldn't possibly use Narutos chakra there? Though I didn't check if he really did. I just think I remember it? xd
#1 Death Reaper/Minato, doesn't matter. My point is: Kurama doen't have it.
#2 Before I can retort, please give me an example of your ref to the Mizukage. I would like to see some of these "jutsu" that don't require Yin/Yang.
#3 Kurama being inside Naruto does mean he can access Naruto's Yin chakra. They have a symbiotic relationship. They are one and the same, pretty much. Naruto feels Kurama some of his chakra and Kurama does the same. So, if Kurama could have spurts of influencing/controlling Naruto, why do you think he couldn't have some access to Naruto's Yin chakra?
Let me know what ya think.