That is true from what I have read. Actually in his books he refers to Naha te as Shorei ryu and Shuri te as Shorin ryu. I believe that Azato was a student of Hiagoanna. I am definetely sure that with looking at some of the kata of Shotokan, which do not come from the Shorin ryu that he did study or exchange knowledge with Mabuni and he and Mabuni were friends. Mabuni was actually his senior in years of karate study even thought Funakoshi was older.
This is a quote from Funakoshi's book "Karate-do, My life."
"Meanwhile, I continued assiduously with my karate, training under a
number of teachers: Master Kiyuna, who with his bare hands could strip
the bark from a living tree in a matter of moments; Master Toonno of
Naha, one of the island's best known Confucian scholars; Master Niigaki
whose great common sense impressed me most deeply; and Master
Matsumura".
Master Toonno is Higaonna and Niigaki is Aragaki.
Itosu and Azato's teacher was Matsumura.
Funakoshi's connection to Naha-te is directly linked the it's founder.
How much influence I don't know. I do not see much in the way of
the kata practiced. Of course, things have changed since Funakoshi's
passing. Execution and interpretion of kata is different under the JKO
than when the founder was still alive.
My observance of the remaining Tomari-te is from the Shobayashi and
Matsubayashi schools of Shorin. They have a stronger influence than the
Kobayashi school. The use of shiko dachi is much more extensive.
Shotokan is kobayashi derived. Itosu taught Funakoshi and Chibana.
Goju's sanchin rooting is not any different from Shorin's naihanchi dachi.
Other than one foot being in front of the other, they both create tension
in he lower body to create rising power. This enables the practitioner
to use techniques like uppercuts and elbows more efficiently. Uprooting
an opponent is easier from this position.
