It looks like the Ammonia one on Aquilo can still be unlocked just fine. And as the only thing it's needed for is something unlocked on Aquilo, this seems fine? It's quite intentional that Solid Fuel isn't a thing in this mod.
You should be able to make sulfur from the sulfide after researching Sulfur Processing, the same tech that lets you treat all the oil fluids
I can see the recipes for solid fuel and sulfur in the factoripedia, I have the tech unlocked I just cant select the recipes in the chemical plants..... by not select them I mean they do not appear in the chemical plants as a selectable recipe.
latest version for everything, standard version of factorio as far as I can tell. Its really frustrating as I can get around everything else (like solid fuel) I just cant progress without sulfur lol