Awesome essay, venerable, thanks so much. It makes a lot of sense, especially the idea of anidassana being equivalent to arūpa. We’d certainly find, I think, that a closer look at the Upanishads reveals more references to something like the dimension of infinite consciousness.
I also like the idea of swapping the sequence of terms. You are quite right, this is the kind of thing that is done all the time, and clearly ananta should be taken as the primary adjective. Maybe I’ll update my translation.
The term pa[b]haṁ has two readings, from pajahati “giving up” or pabhā “light”. There’s no really strong reason to choose one or the other, so I am open to being persuaded!