Haga Junichi was the one who said that Ueshiba was the best swordsman in Japan. On the other hand, a person expert in classical sword spoke scornfully to me about the way Ueshiba executed yokogi-uchi (hitting the bundle of sticks, a Yakumaru-ha Jigen-ryu practice), because, done properly, one strikes exactly the same point every time (until the sticks break), whereas films of Ueshiba show him hitting the sticks at various portions. (The swordsman said to me, "He's doing exercise, not kenjutsu).
As for where Ueshiba learned what, I'm not aware of any records or accounts of Takeda teaching Ueshiba in detail. However, I've seen one article in Hiden magazine where the writer uses photos of pretty much all the major figures in Daito-ryu and some of Ueshiba's major students as well, to establish that there are several components (technique) that are common to all of them.
Ueshiba is known to have taken other people's forms and saying, "in aiki we do it this way," which suggests that he used sword kata as vessels to hold what he considered his primary study. Among the ryu that he used in this way were Yagyu Shinkage-ryu and Kashima Shinto-ryu.
I could go on for quite a few pages, but - oh yes! It's already been done. HIPS - "A Unified Field Theory: Aiki and Weapons