For the form חריתא/חרותא in the passage from BT Qid 81b(12) see now the discussion of Michal Bar-Asher Siegal in "Syriac Monastic Motifs in the Babylonian Talmud:
The Ḥeruta Story Reconsidered (b. Qiddushin 81b)*" in Jews and Syriac Christians:
Intersections across the First Millennium, ed. A.M.Butts and S. Gross (Tübingen, Mohr Siebeck, 2020), pp. 27ff.