Board Thread:Naruto Discussions/@comment-27550669-20190130125246/@comment-6769189-20190204024738

Perfect Jinchuriki were never confirmed to be immune to genjutsu. In fact the 1st one we saw in the series got hit with one and instantly faceplanted.

Obito could take full control of Kurama while it was still in Kushina, so taking control of the 3 tails shouldnt have been an issue and then controlling Yagura afterwards without them knowing shouldnt be too hard for him