Koen,
That's another good find. I don't think either of us (do we?) think the manuscript's about Egyptian religion, but I think it should be said plainly that we're talking about the forms found in the imagery which constantly, and consistently, refer to the eastern or southern Mediterranean.
The way I see it, these elements add to the likelihood that Baresch really did know something about the manuscript and its provenance. There's more in favour of his saying the source was "Egyptian" in some way than for any connection to Rudolf. Nothing in the manuscript suggests that. Plenty does support Baresch's comments.
Like you, I lean towards Greco-Egyptian (Hellenistic) period for the sources from which the imagery derives.
Here, for example is the model which I think also informs the "fairy with wand" image in the manuscript.
and here's the 'handfast' pair:
I could go on, but you get the picture.. I think the 'angel with star-shield' is the most interesting by far because we can date the medallion to the early Hellenistic period, while Egypto-Persian culture was still strong within Egypt.
This raises the interesting possibility that the series is on this long, long foldout because transcribed from an original that could have been on papyrus. Even in parts of Europe, papyrus was being used as late as the 11thC. It was employed by the Normans in Siicily, and by the Popes. Not impossible.
Oh - and of course the Scales which are nothing like those in European or Islamic manuscripts. They *always* - without exception - show the trays or baskets tied or fastened directly to the crossbeam like this
Like this, and the next one
But as you'll see though surprisingly many people apparently can't - here we have a narrower thing, here drawn like a rod, which passes though the crossbar's (hollow?) centre, with the trays hanging from that.
Now, if there were ever scales like that used in medieval Europe I've yet to see them, and I don't limit the search to nice manuscripts.

I think what the original looked like was something more like a type you find in the older, and eastern side of the Mediterranean. I'll show a hand-held and a couple of standing versions: (note the hear-shaped weight). In the first image it means 'gold standard'.
and here is the Egyptian form, the outdoor, mercantile version
and the indoor 'Pharaonic' version
I hope you don't think this is "off topic" for patterns. I think it shows that your suggesting the patterns might derive from the practices of Egyptian scribes and artisans finds support elsewhere in the same folios.