Greetings,
Firstly I would like to say that this is great mod.
I am currently playing with this modification, at the stage of all oil-related pre-chemical science research unlocked, except for [Tar sand mining] and [Natural gas extraction].
I have noticed, that in Factoriopedia, there are recipes for [Solid Fuel] available to be made from: [Gasoline], [Petroleum Gas], [Naphta] and finally [Fuel Oil].
However when selecting [Chemical Plant] building, there is only recipe for [Solid Fuel from Gasoline], which is also visible as unlocked from [Basic Oil Refining] technology.
The other variants seem to be just shown in Factoriopedia with no related technology to unlock said recipe.

Is there something I am missing, or there is in fact, no way to make Solid Fuel from Naphta/Petroleum_gas/Fuel_oil in current version of the mod?

It can only be made from gasoline

And this was only added because space age added something that uses it, so I had to add a way to get it.

So as the generic end fuel, gasoline was the obvious choice for that

I have noticed that there are few more recipes that are unavailable. Thank You for responding!
So I guessed, that they are left in-game but actually not available.