1. Incorrect. The Yagyu scroll was Yagyu Shingan-ryu. There was nothing for Yagyu to discredit. Different ryu. Also, I've never heard before that Yagyu sensei reviewed the certificate. Muto Masao, headmaster of YSR certified it as genuine Yagyu Shingan-ryu. Also, Ueshiba DID learn some Yagyu Shinkage-ryu and this was recognized by Otsubo shihan of Shinkage-ryu. See my (ahem) b o o k.
I meant Yagyu Shingan when I wrote Yagyu-hey it was late here....
That said, I'll have to look it up but i am quite sure it was questioned. I think Yagyu Sensei said something like, it wasn't signed, or it looked fishy.
Regardless none of that was the point.The point was what he decided to do when he first taught.
Two things remain that were witnessed
When he met Takeda, he quite literally ended up crying in the corner.
Seven years later...when he decided to teach for the first time, he showed up in formal attire one morning at ayabe and announced to his nephew. "I am finally going to be a jujutsu teacher." From then on he taught Daito ryu.