I am using the pack FTB Infinity Evolved v2.1.3 and I am unable to craft Electrical Steel in an alloy smelter.

Whether I use the all smelting function or alloys only, it will not allow me to craft Electrical Steel.

I can add either Iron or silicon into the gui, but never both. It will not allow me to add pulverized coal (Thermal Expansion) or Coal Dust (IC2).

Are you sure that is the recipe?

Yes. It is displayed in NEI as well as in the recipes page in the Alloy Smelter GUI.

Turns out I cant craft a reservoir either. Perhaps the modpack has an issue or Ender IO has a few bugs?

It's unlikely our recipes simply don't work, as that would be quite a large issue (many reports). I'd check with your server owner (if applicable) or the pack creator.