What does this:
# Register alternative redstone, glowstone, cryotheum and ender fluids? It is recommended that this is set to true if no CoFH mods are installed.
B:register_cofh_fluids=true
exactly do?

I set it to true, as i no longer have anything from CoFH - but e.g. enderium is still unavailable?

Perhpas look up 'molten ender' instead?

Well i can't craft the enderium cooler, while i can with the crytoheum for example - it's made out of tin, it seems.

You can craft the cryotheum coolers?

Yes. They're made with molten crythoeum which can be made out of tin and beewax in forestry.
Molten Ender is there but has no recipes. The enderium cooler also has no recipe.

Your molten redstone and glowstone also have no recipe - but i can use the one from enderio for redstone. For glowstone there is no alternative.

Maybe there is something wrong with the molten things? You maybe could also make them tinkers compatible.

Yeh, the reason you can't make enderium coolers is because they require enderium, not just ender pearls or molten ender.

Can you not produce NC's molten redstone, glowstone and ender in the Melter?

No.
Glowstone = Glowstone Gas (Ender IO)
Redstone = Molten Redstone (Ender IO)
Ender Pearls = Liquefied Ender Pearls (Ender IO)

Evil Ender IO.

But that's fine - those fluids will still be valid active coolants.