Re: ueshiba and chinese martial arts
I have always thought of aikido as A (not THE) practical application of tai chi. I have made it a point to supplement my aikido training with the Yang Family form. I also thought it was interesting that Tamura Sensei, who spent a great deal of time with O'Sensei, demonstrated tai chi (chi gung) as a warm up during camp.
I think there may be something to the idea that O'Sensei used the principles if not a specific form of Chinese internal arts.
Whether it's tai chi, yoga, or ba gua, having an internal practice is very important in gaining a higher understanding of aikido.