a. It was their internal training that made them exceptional. Their spiritual pursuits did nothing to aid in their budo power
Well I submit that Ueshiba, at least, did not see any difference between his internal training and his spiritual pursuits, they were one and the same to him. This raises the question as to whether or not Takeda, Kodo, or Sagawa thought of the goals of their solo internal training in terms that we relate to if we reduce the practice to a means to "martial power." I don't think so but there is not enough data there.
With Ueshiba, though, it's pretty clear, isn't it? "Spiritual pursuits" were what he obsessively spent the last couple decades of his life doing. Or have we all analyzed the text and realized that when it seemed like he was talking about fixing the universe he really just wanted to be able to hold a stick better?