Goju Ryu has its origins in the teachings of Kanryo Higashionna which were classified as Naha Te and his personnel way as Shorei Ryu or Enlightened spirit style. Higashionna's Chinese teachers are by tradition considered to be Ryu Ryuko, the Chinese teacher of Whooping Crane (Minghe Quan) and his assistant Wai Shin Zan (also Wan Shin Zan and Wai Xinxian). Martial Art historian Patrick McCarthy in his meticulous researches into the origins of Karate has identified Ryu Ryuko as Xie Chongxian 1852-1930.

Kanryo Higashionna 1853-1917 was just one of several Okinawan students who travelled to Fuchou in the province of Fukien, China and studied with Ryu Ryuko.

Yet before Higashionna went to China, as an adolescent he had studied Naha Te under karate master Sheisho Aragaki, (also Arakaki (Japanese))1840 - 1920. Aragaki himself is reputed to have studied in Fuchou with Wai Shin Zan.

Other contemporaries who studied in Fuchou were Isei Kojo (1832-1891) and in later years his son Kaho Kojo(1849-1925) both who studied Kempo with Iwah, a military attache. After being awarded his teachers licence Kaho Kojo and his assistant Makabe opened a dojo in Fuchou.

Another member of the Kojo family; Taitei Kojo 1837-1917 studied Kempo with Wai Shin Zan.
Norisato Nakaima (1850-1927) studied with Ryu Ryuko from @1860 to 1866 after which he received his teachers licence. On returning to Okinawa, the teachings were past on in secret as a family tradition until 1971 when Kenko Nakaima for the first time taught openly naming it Ryuei-ryu.

Thus the major influences and the contemporaries of Higashionna may have looked something like this:

                                Ryu Ryuko
                                ____|__________
                               |    |          |
   Iwah               Wai Shin Zan  |          |
    |                  ____|_____   |          |
    |                 |    |     |  |          |
Isei Kojo             | Aragaki  |  |  Norisato Nakaima
    |                 |    |     |  |          |
Kahi Kojo - Taitei Kojo    |     |  |   Nakaima family
    |                      |     |  |          |
Kojo Family ------------- Higashionna ---------

With Aragaki introducing Higashionna to the Naha Te kata Sanchin and Seisan this might suggest that he (Aragaki) learnt these from Wai Shin Zan. Aragaki may well given the young Higashionna an introduction to study with Wai Shin Zan in China.

What is known is that Wai Shin Zan was Ryu Ryuko's assistant but probably had knowledge of martial styles not practised by Ryu Ryuko who was still formulating his own method of Crane Boxing.

Students would often study with multiple teachers learning several martial arts. In turn they might hand on the individual styles or synthesise what they know into an eclectic teaching. Wai Shin Zan could have been teaching a composite style of Peho (Fukien White Crane), Lohan (Monk Boxing) and Tat Chun(Tamo iron body).It has been suggested that Wai Shin Zan may have been a teacher of Five Ancestors which was founded on Peho, Lohan, Kao Kun (monkey boxing), Tai Cho (great ancestor boxing), and Tat Chun (Tamo iron body)

With Wai Shin Zan assisting Ryu Ryuko during a period of evolution this could account for changes between the earlier forms of Aragaki and the later forms of Higashionna.

Whilst Higashionna didn't openly teach Ryu Ryuko's crane forms on his return he was profoundly influenced by the Crane Boxing principles.

The core of Higashionna's teaching was quite possibly an eclectic rather than a traditional art. This may have been based on Lohan boxing and Tamo iron body training integrated with a composite of Ryu Ryuko's and Wan Shin Zan's Crane boxing.

Whatever the true origin's are, should they ever be discovered, Higashionna passed on a synthesis of martial knowledge that is relevant whatever its source. We can therefore look back in appreciation at the rich heritage the early Okinawan karate teachers handed down irrespective of Ryu. Equally we should look forwards and understand that all karate below the surface is the same, as the differences are but expressions of a common knowledge.

References:
Fighting Art International: No.87 and No.90 The Black Ship of Karate-Do 'Patrick McCarthy' by Colin Whitehead and Graham Noble.
Okinawan Karate, 'Teachers, styles and secret techniques' by Mark Bishop, printed 1989 A&C Black, ISBN 0 7136 5666 2.