Update: Images Working 
It took a weekend of tinkering off and on, but I finally have image displaying working using WiringPi.jl!
I had to go back to the original library from WaveShare to figure out how to prepare images. As it would turn out, I had to reimplement some of the dithering abilities from the PIL Python library and do a bunch of byte-packing based on @stene 's suggestion. I got a little prototype working and now we shall do some cleaning and package preparation!
However, now that I have figured out how to drive an e-ink display with a Raspberry Pi using Julia, I suppose we can close this discussion for now!
I’ll make another discourse to share about further hardware experiments.
P.S. The display image here was made using Makie with the CairoMakie backend! 