The ezafet particle in Middle Persian is /ī/ (or /īg/), like /-e/ in later Persian, but in Parthian it's the interrogative/relative /čē/ that serves the purpose, e.g. /mād čē dēwān/ "mother of demons".

It's just the number "one"

Yes, I took /wāyōg/ as in apposition to /mard/ (≈ "there was a person, a hunter"), with /wāyōg/ as the antecedent of /kē/ (not /mard/ strictly speaking)

No, I don't really have any ideas as to the origin, just that given the geographically limited attestation it seems most likely that the direction was Coptic > Egyptian Arabic, and that a Semitic origin seems unlikely, since, as you say, there's no obvious occurrence beyond the Eg. Arabic word.

Yes to all that! 😎

And with a few more photos here

Obviously, that should be Acta Pauli

Cf. Egyptian Arabic /hallūs/ "cobwebs" (Badawi & Hinds 910b, recognized as Coptic), but maybe also the spider itself, too (cf. Vycichl 297b). As usual, Černý assumes it's a Semitic lw in Coptic, but it's probably the other way.

"And angles ministered ill"

This week I read an Old Uyghur text with the word /(y)ıš/ "mountain forest, mountain meadow" (Bergwald, Bergalm), which looks like it would fit here.