Over too much time spent thinking about the chemistry of Factorio, I concluded that there's no discernable difference between "coke' and "solid fuel". Solid fuel, I would argue, is really a sci-fi supercoke. My recommendation is that in the cases where you were going to use coke from another mod, consider using a solid-fuel item when that other mod doesn't exist.

That's a good idea for solid fuel. I'll probably use it as an option if Coke is not present in my upcoming foundry/smelter/furnace-thingy mod.