Re: Minato the host.
First of all, you need to understand the DRS.
Hashirama and Tobirama were also sealed inside Hiruzen, so was Oro's arms. But they are outside the seal now. So would the kuybi chakra most likely be.
If not, of course, you also make another misconception. Minato can't be a host. He only sealed part of the Kuybi's chakra. It has nothing to do with a jinchuriki. He would just gain some freak-like version of the Kuybi, resembling that of Gin/Kin bros.
Of course Minato would have much more than them, thus obtaining more power, when using it. However, probably not capable of controlling it.