@Ratatosk
I am what you refer to as a "Bijuu Owner" and also have multiple Kekkai Genai/powerful traits/techniques. As Bocchiere noted, that is permissible by the "sixteen-point" norm. However, in relation to the biju, I wouldn't say that they add more power to their jinchuriki.
Let me be clear. I think that they should. But descriptively speaking, I don't really think they do. Rather, I think that the biju have two values.
(1) A biju, while not "owned" by anyone IC, is essentially controlled by whoever their respective jinchuriki is. This additional conscious entity allows for more diverse and interesting RP.
(2) Also, to some people, the biju are a sign of skill, and earn their jinchuriki respect. Mostly, I think, in cases where the biju was actually attained by means of skill rather than their jinchuriki going inactive. Sadly, inactivity has been the norm lately rather than respectfully-handled battles of RP skill.
The value that biju should offer is substantial chakra boost, but as it has been pointed out, it is no longer the norm to limit chakra use on SL.
Thus, I don't see any real power being added to anyone -- regardless of their unique kekkai genkai or other trait claims -- simply by them possessing a biju.