Sorry, I'm going to have to ask you to elaborate a little bit for me, as I'm canonblind on this particular point - is the Kyuubi as you're referring to it here more of an attack, or more of a power-augmenter?

It sounds as though you're describing Kushina being able to draw on the power of Kyuubi in order to do...something (attack, presumably, but again, I'm canonblind so I'm having to speak in general terms here), and I just want to make sure I actually understand her scenario before I try to give you an answer!