That's not how any of this works!!!!!!
I would side on that's not how defensive was intended, however there seems to be a precedence set. Interact is also worded as a (#) and you can definitely take two different AP(1) interact actions. So I would say that doing two different defensive AP(1) actions is not intended, but I would also say that your statement about the rules not limiting that is accurate.
As for the topic at hand, I tend to slingshot Mr. Nothing beast with Tara, however I always take KoE and use the + on initiative to have Tara pull him back in the void to keep him alive at the start of the next turn. I've found even with Void Shield he is still a glass cannon and if I keep him out, he dies.