Melkite Arabic disputation

As I was considering Mingana - and BarSalibi and Nicetas - I moved to considering what sort of collection of Christian controversy might have inspired those two, to compile Arabic text in West-Syriac and in Greek (respectively). A brief check upon Hoyland turned up pap. Schott-Reinhard 438 (apparently now catalogued "MS Heidelberg, Institut für Papyrologie, P. Heid. Inv. Arab. 438 a-d") and "On the Triune Nature of God".

The latter Sinai 154 was penned at the turn of the AD 8/9th century, Sinai/Negev: Juan Pedro Monferrer-Sala (2010) doi 10.1086/597764. Its content was edited and published eleven centuries later, by one Margaret Dunlop Gibson. This was so long ago, that a lot went missing - as happened to Agapius on his way to Vasiliev. Also, Mrs Gibson likely used a chemical to bring out the faded lettering, which damaged the text for future readers. This is all lamented by Samir Khalil Samir working from a new photo taken in 1994.

The seminal pre-Samir paper is Rendel Harris "A Tract on the Triune Nature of God", who was not an Arabist and admits as much. Harris cared most for what the Tract said about this Arab's use of Biblical material. He found that it is ancient and even paraBiblical in parts; repeating apologetics against the Jews back to the days of Irenaeus and (especially) Justin, who did not use Westcott and Hort. The Tract would, then, not be a witness to the Arabic Bible (not even to "the gospel"). This argument is the argument which Sidney Griffith has been arguing, with some force.

For the Arabic of the Tract Hoyland points rather to John Wansbrough, who in one of Sectarian Milieu's more comprehensible moments flags the Tract's Arabic as, specifically, Qâric.

The text is not the autograph. In fact in this papyrus itself, the essay follows upon a translation of Acts (from chapter 7) and then the Catholic Epistles. The translation was done in an archaic hand, one assumes from an 'Abbâsî MS. (Gibson offers a photo. She's not joking!) The Tract is more modern in style. Some would date the autograph to the AD 750s / AH 130s, under al-Saffah or maybe Mansur. Either way it smells like a predecessor to Theodore.

I don't know that the Tract owned any Greek. Did the Tract use Palaestinian Aramaic or Syriac, to learn how to dispute the Tawhid?