I know there is a mystery about Nohime's death. Onabe no kata's grave is at the same place as Nohime's Soukenin Temple at Daitokuji. Onabe no kata died a few weeks earlier. She passed away on June 25, 1612. As for the grave mount picture I posted earlier. It is Nohime's. God bless her.
More information please read Okada Masahito's Oda Nobunaga Soogyoo Jiten, pp. 165-7.
Nobunaga no Tame!