Post #20.
The back cover that that post refers to states that Lamsa's translation is based on the
peshitta. The wikipedia link states that the New Testament version of the Peshitta is based on a translation from the Greek:
The Peshitta (Classical Syriac: ܦܫܝܛܬܐ pîṭtâ) is the standard version of the Bible for churches in the Syriac tradition.
The consensus within biblical scholarship, though not universal, is that the Old Testament of the Peshitta was translated into Syriac from Hebrew, probably in the 2nd century AD, and that the New Testament of the Peshitta was translated from the Greek.[1] This New Testament, originally excluding certain disputed books (2 Peter, 2 John, 3 John, Jude, Revelation), had become a standard by the early 5th century. The five excluded books were added in the Harklean Version (616 AD) of Thomas of Harqel.[2] However, the 1905 United Bible Society Peshitta used new editions prepared by the Irish Syriacist John Gwynn for the missing books.
My quick impresssion is that the Peshitta is different from the Hebrew Gospel hypothesis. I'm going to read further to see if I can find a connection.