Far as I know, Saigo Shiro was either the adopted son or illegitimate son or both of Hoshina Chikanori, who is also know as Saigo Tanomo. And as far as I know, that 1886 tournament happened.
Unless you know otherwise?
Saigo Shiro, born 1866. In 1882 he joined the Kodokan (sixteen years old). He was adopted by Hoshina Chikanori, if Ellis Amdur is correct*, in 1884 (18 years old).
At that time Chikanori was living in Nikkō Tōshō-gū -Togichi prefecture- about 140 km north of Tokyo. This means serious commuting from his adoptive father residence to Tokyo for Judo training and back home for aiki in 19th century Japan.
On the 1886 (Shiro being 20 years old) Judo vs JJ matches, there are serious doubts they happened as we have been told
*See HIPS, p. 75-76