A discussion of spirituality on aikiweb would not be complete without you!
One point, center, hara, koshi, kokyu, every one of them can be found in ascetic and spiritual practices. Ueshiba realized that the form and techniques of Aikido were a perfect vehicle for such ascetic practices.
To my mind, this a clear explanation of the ecumenical nature of aikido as spiritual pursuit. Train the spirit first and the rest will follow kind of approach. I would be interested in reading any quotations you have found that highlight this perspective.