Everything I've read suggests otherwise. Ueshiba dabbled in a few martial arts but never really stayed with them long ... until he met Takeda. Daito ryu is the one and only art that Ueshiba stayed with, became a teacher of, and then progressed on his own.
As for "competition", I would research what Peter Goldsbury had to say on that subject. Very illuminating. It's here on Aikiweb somewhere. Basically, there are different definitions of "competition" and Ueshiba was okay with some but not others. Competition between peers to become better - okay. Olympic Judo type competition - no.
In the article Stan posted yesterday, the self-defense world translation of his Asahi interview, Ueshiba keeps things vague enough that one could run with the idea that he ran around mastering various arts and challenging people, but I would agree with you that the timeline just doesn't seem to support it being as extensive as it sounds. DR is definitely the only one that stuck with him though.