folio 85r2 possibly representing the 4 academic faculties

[Koen G]

Indeed, the figure with the vessel as Medicine is not a problem. Even if this weren't intended as a urine flask, one can still argue in favor of a vial of medicine or whatever. I am convinced the medieval viewer would have recognized this figure as "a physician" without a second thought.

Theology is, in my opinion, your proposal's biggest problem. In medieval stock images, the figure bent over a cane with prayer beads is rather read as "old" instead of "saint". Everyone would have had prayer beads in their household - this would not have been a specific marker of holiness. Moreover, the art of Theology is really about being learned, able to interpret scripture, rather than necessarily being a paragon of virtue (although early theologians, church fathers... would often become saints of course).

Why were old people so often depicted with prayer beads? On the one hand, this must have reflected some medieval reality. But the message is foremost a moralizing one: when your body no longer allows you to work the fields and death is right around the corner, your main concern should be with the soul. Pray those sins away, cleanse your soul, get ready to meet your maker. Old people bent over a staff are shown with prayer beads because praying to cleanse sins was all that was left for them to do on this earth. This has very little to do with one learned in Theology. It simply shows this person's attention has shifted away from their earthly, decaying body and towards the eternal.

The Trinity is a great symbol for Theology because only theologians understand it ;)

Flowers for rhetoric might work, although flowers were the medieval artist's favorite metaphor. Things of beauty, things of theological significance, youth, spring, the Virgin... A collection of flowers (Lat: florilegium, Gr: anthologia) was a gathering of excerpts from other text, often to make theological points. See also the "Liber Floridus". But this one isn't problematic.

The pointing gesture can mean that someone is speaking, and often shows that someone speaks with authority on a subject. Often shorthand for a scholar. See "Magister Iulius" in your woodchopping picture.

So in short:
Figure with vial: could stand for medicine or one of its subdisciplines, this is OK
Figure with cane and loops: preferential reading is old age. Even if the reading is "saintliness", that is not the same as "learned in Theology"
Figure with flower: could be rhetoric, but flower symbolism is very non-specific.
Pointing figure: stock pose of the scholar, could stand for any discipline.