Yup, yup, I understand what you're saying and I agree with you about Gedo Mazo being like the host of all the bijuu he has.
But what I'd like to point out is that the moment Naruto destroyed the rod that was binding Son Goku and Roshi, Son was completely seperated from his host.
Here, Son refers to the rod as a temporary way to bind his chakra to Roshi.
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Meaning that when it's destroyed, Son is no longer trapped in the jinchuuriki.
So, Kabuto might have control over Roshi, but he wouldn't have control over Son Goku, because the bond between Son and Roshi would have been severed.
