The sequence of images

[Linda]

I think it is logical to assume that the water represents the same thing in all of these pages. The imagery is so similar, obviously a similar theme is being referenced.

I think just the opposite.
F82r, why is the nymph standing in blue water on the side? If it didn't matter, why not green?
F84r, different bath colors.
Maybe you should look at it that way:
black coffee, coffee with milk, black and sugar.

It makes sense from a procedural point of view.
Grapes become juice, juice becomes wine.
Refinement: wine, brandy or vinegar.
From a medical point of view around 1400, absolutely comprehensible.

Water with salt or other minerals vs water with no inclusions, perhaps? (Coffee with milk and/or sugar, vs black, black is blue) 

Note that she has a tube, tubes are rivers. I see her as representing Colchis, which might work well with the OP idea of the Golden fleece being involved, both the myth and the order, with Geoffroy de Thoisy becoming pirate pimp in the name of Burgundy while at Colchis in 1444. So maybe more connections can be made of the disparate images, mythology and religion in this case.