seems rather simple to at least get it running (haven't done more than a few minutes of testing, apologies)

In data-final-fixes.lua:ln70 change to recipe.categories = {crafting_category.name}

In data.lua:ln53 change to quality_holmium_solution_recipe.categories = {holmium_chemistry_category.name}

and of course updating the info.json compat number.

update: ah, buggar seems there is more to it. If I build a new holmium chem plant I get extreme sadness. I'll try to poke when I have time over next few days...

Error for ref if anyone else has ideas:

Error while running event quality-holmium-ore-returns-more-holmium-solution::on_robot_built_entity (ID 18)
LuaEntity doesn't contain key fluidbox.
stack traceback:
        [C]: in function '__index'
        ...-holmium-ore-returns-more-holmium-solution__/control.lua:347: in function 'on_holmium_chemical_plant_changed_quality'
        ...-holmium-ore-returns-more-holmium-solution__/control.lua:329: in function <...-holmium-ore-returns-more-holmium-solution__/control.lua:104>